SELECTION OF ARTICLES

Transcription

CENTRE de DOCUMENTATION
de l’INSTITUT NATIONAL DE L’INFORMATION
GEOGRAPHIQUE ET FORESTIERE
centrededocumentationdel'IGNcentrededocumentationdel'IGNcentrededocumentationdel'IGNcentrededocumentationdel'IGNcentrededo
cumentationdel'IGNcentrededocumentationdel'IGNcentrededocumentationdel'IGNcentrededocumentationdel'IGNcentrededocumentatio
ndel'IGNcentrededocumentationdel'IGNcentrededocumentationdel'IGNcentrededocumentationdel'IGNcentrededocumentationdel'IGNce
SELECTION OF ARTICLES
referenced between March 1
and April 30, 2012
IN ENGLISH
May 2012
bulletin 25
CENTRE DE DOCUMENTATION DE L'IGN
6/8 Avenue Blaise Pascal - Cité Descartes - Champs sur Marne 77455 Marne la Vallée cedex 2
Tél. : 01.64.15.32.80
Télécopie : 01.64.15.32.84
Mél : [email protected]
Site Web : http://www.ensg.eu
Inside each item, references are ordered by publication date and author alphabetic order.
Contents
Geographical information systems GIS............................................................................................ 3
Geomatics
............................................................................................................................. 3
GIS applications ............................................................................................................................. 5
Image acquisition............................................................................................................................. 6
Image processing............................................................................................................................. 6
Lasergrammetry ........................................................................................................................... 10
Navigation and positioning............................................................................................................. 11
Radar image processing................................................................................................................ 11
Remote sensing applications......................................................................................................... 14
Signal processing........................................................................................................................... 15
Spatial analysis ........................................................................................................................... 17
Spatial databases........................................................................................................................... 19
Spatial data infrastructure.............................................................................................................. 20
Webgeomatics
........................................................................................................................... 21
_______________________________________________________________________________________
Centre de Documentation de l’IGN – p. 2
Geographical information systems GIS
Titre
Auteur(s)
Source
Mots clés
N° notice
Résumé d’auteur
Topological operators: a relaxed query processing approach
BELUSSI (A.), CATANIA (B.) et PODESTA (P.)
GEOINFORMATICA, vol 16, n° 1, [01/01/2012], pp 67 - 110
Titre
Producing an indigenous knowledge Web GIS for Arctic Alaska communities:
Challenges, successes, and lessons learned
EISNER (W.), JELACIC (J.), CUOMO (C.) et al.
TRANSACTIONS IN GIS, vol 16, n° 1, [01/02/2012], pp 17 - 37
OPERATEUR SPATIAL, RELATION TOPOLOGIQUE, REQUETE SPATIALE
A2012-082
Relaxation and approximation techniques have been proposed as approaches for
improving the quality of query results, in terms of completeness and accuracy, in
environments where the user may not be able to specify the query in a complete and
exact way, since data are quite heterogeneous or she may not know all the
characteristics of data at hand. This problem, mainly addressed for relational and XML
data, is nowadays quite relevant also for geo-spatial data, due to their increasing usage
in highly critical decisional processes. Among geo-spatial queries, those based on spatial
and more precisely topological relations are currently used in an increasing number of
applications. As far as we know, no approach has been proposed so far for relaxing
queries based on topological predicates when they return an empty or insufficient
answer, in order to improve result quality and user satisfaction. In this paper, we consider
this problem and we present a general relaxation strategy for, possibly multi-domain,
topological selection and join queries. Two specific semantics are also provided: the first
applies the minimum amount of relaxation in order to get an acceptable answer; the
second relaxes the given query of a certain fixed amount, depending on the considered
topological predicate. Index-based processing algorithms, for efficiently executing relaxed
queries based on the proposed semantics, are also presented and a specific topological
similarity function, to be used for relaxation purposes, is proposed. Experimental results
show that the overhead given by query relaxation is acceptable.
Auteur(s)
Source
Mots clés
SIG PARTICIPATIF, WEBSIG
N° notice
A2012-096
Résumé d’auteur A traditional knowledge “Iñupiaq Web GIS”, based on a five-year study and containing
observations and environmental knowledge of Iñupiat communities indigenous to Arctic
Alaska, was incorporated into a Web-based platform. The website, “Arctic Cultural
Cartography,” was created to be an open portal through which the password-protected
“Iñupiaq Web GIS” could be accessed. We discuss the process of developing the web
GIS including the incorporation of user-friendly features such as links to interactive maps,
video clips of interviews, discussion boards, and the integration of popular web interfaces
such as Facebook. We also discuss short- and long-term goals for the further
development of the GIS, its potential as a sustainable, participatory online database for
sharing pertinent ecological knowledge, and challenges in achieving optimal community
involvement given constraints imposed by remote locations with limited bandwidth.
Geomatics
Titre
Auteur(s)
Source
Mots clés
Provably correct and complete transaction rules for updating 3D city models
GROGER (G.) et PLUMER (L.)
BASE DE REGLES, CITYGML, COHERENCE GEOMETRIQUE, EXHAUSTIVITE DES DONNEES,
MISE A JOUR DE BASE DE DONNEES, MODELE 3D DE L'ESPACE URBAIN, OBJET
GEOGRAPHIQUE COMPLEXE
N° notice
A2012-084
Résumé d’auteur The shapes of our cities change very frequently. These changes have to be reflected in
data sets representing urban objects. However, it must be assured that frequent updates
do not affect geometric-topological consistency. This important aspect of spatial data
quality guarantees essential assumptions on which users and applications of 3D city
models rely: viz. that objects do not intersect, overlap or penetrate mutually, or
_______________________________________________________________________________________
completely cover one another. This raises the question how to guarantee that geometrictopological consistency is preserved when data sets are updated. Hence, there is a
certain risk that plans and decisions which are based on these data sets are erroneous
and that the tremendous efforts spent for data acquisition and updates become vain. In
this paper, we solve this problem by presenting efficient transaction rules for updating 3D
city models. These rules guarantee that geometric-topological consistency is preserved
(Safety) and allow for the generation of arbitrary consistent 3D city models
(Completeness). Safety as well as completeness is proven with mathematical rigor,
guaranteeing the reliability of our method. Our method is applicable to 3D city models,
which define—besides the terrain surface—complex spatial objects like buildings with
rooms and storeys as interior structures, as well as bridges and tunnels. Those objects
are represented as aggregations of solids, and their surfaces are complex from a
topology point of view. 3D GIS models like CityGML, which are widely used to represent
cities, provide the means to define semantics, geometry and topology, but do not address
the problem of maintaining consistency. Hence, our approach complements CityGML.
Titre
Auteur(s)
Source
Mots clés
Agent-based modeling of stakeholder's interactions in a land development project
in southern Alberta
KIESER (M.) et MARCEAU (D.)
REVUE INTERNATIONALE DE GÉOMATIQUE, vol 22, n° 1, [01/01/2012], pp 31 - 53
ACTEUR, AMENAGEMENT DU TERRITOIRE, HABITAT URBAIN, MODELE ORIENTE AGENT,
POLITIQUE TERRITORIALE
N° notice
A2012-076
Résumé d’auteur Cet article présente une modélisation agent dans le but de simuler le processus de
planification d’un développement territorial dans une zone résidentielle de Strathmore
dans le sud de l’Alberta (Canada). Le modèle se concentre sur les interactions et le
processus de décision via trois partenaires : le développeur, le planificateur et le citoyen
qui joue un rôle central dans le processus. Ce modèle prend en considération les
facteurs sociaux et économiques qui influencent ces acteurs selon les règles
gouvernementales, les politiques de planification et les politiques suivies pour la
réhabilitation des territoires. Le modèle a été calibré en utilisant des entrevues et des
documents existants.
Titre
Auteur(s)
Source
Mots clés
An evaluation of internet versus paper-based methods for public participation
geographic information Systems (PPGIS)
POCEWICZ (A.), BROWN (G.), NIELSEN-PINCUS (M.) et SCHNITZER (R.)
EVALUATION DES DONNEES, INFORMATION GEOGRAPHIQUE VOLONTAIRE, SIG
PARTICIPATIF, SUPPORT ELECTRONIQUE, SUPPORT PAPIER, UTILISATEUR CIVIL
N° notice
A2012-097
Résumé d’auteur Public participation geographic information systems (PPGIS) are an increasingly
important tool for collecting spatial information about the social attributes of place. The
availability of Internet-based options for implementing PPGIS presents new opportunities
for increased efficiency and new modes of access. Here we used a mixed-mode
approach to evaluate paper versus Internet mapping methods for the same PPGIS
survey in Wyoming. We compared participant characteristics, mapping participation, and
the spatial distribution of mapped attributes between participants who responded to the
paper versus Internet option. The response rate for those who completed the paper
version of the survey was nearly 2.5 times the response rate of the Internet version.
Paper participants also mapped significantly more places than did Internet participants
(43 vs. 18). Internet participants tended to be younger, more likely to have a college
degree, and had lived in the region for less time than paper participants. For all but one
attribute there was no difference in the spatial distribution of places mapped between
Internet and paper methods. Using a paper-based PPGIS survey resulted in a higher
response rate, reduced participant bias, and greater mapping participation. However,
survey mode did not influence the spatial distribution of the PPGIS data.
Titre
Auteur(s)
Source
Mots clés
Comparison of four line-based positional assessment methods by means of
synthetic data
ARIRA-LOPEZ (F.) et MOZAS-CALVACHE (A.)
DISTANCE DE HAUSDORFF, ESTIMATION DE POSITION, QUALITE DES DONNEES, TAMPON,
VALEUR ABERRANTE
_______________________________________________________________________________________
N° notice
A2012-087
Résumé d’auteur Positional accuracy of spatial data can be assessed by means of line-based methods. In
this work we develop an analysis of the following four methods: Hausdorff Distance,
Mean Distance, Single Buffer Overlay and Double Buffer Overlay, using a set of 12
synthetic cases. The synthetic cases incorporate specific shape features for bias, random
errors and outliers which correspond to simplified versions of real world possibilities. The
use of synthetic cases helps us to understand the basic behavioral differences between
the methods. Numerical results for the positional accuracy estimations are different
between methods and cases due to the different concepts of distance involved and the
specific configurations of each case. When the method results in a function, patterns
related to different types of errors can be detected in this function. The length-inclusion
level of each method is revealed as the base criterion for comparison. The Single Buffer
Overlay Method offers the more general solution because it includes the others’ results.
GIS applications
Titre
Auteur(s)
Source
Mots clés
Monroe county takes to the road with GIS technology vehicle
CORBEY (K.)
GEO: GEOCONNEXION INTERNATIONAL, vol 11, n° 1, [01/01/2012], pp 24 - 26
CARTOGRAPHIE SIMULTANEE, INFRASTRUCTURE NATIONALE DES DONNEES
LOCALISEES, SIG NOMADE, URGENCE
N° notice
A2012-038
Résumé d’éditeur Kevin Corbey reports on a remarkable vehicle, by day, supports infrastructure
construction, asset maintenance, and operations. By night, it serves as a mobile
command center for public safety and emergency operations.
Titre
Auteur(s)
Source
Mots clés
Spatially enabled sustainability indicators
SILHANKOV (V.) et MASTALKA (M.)
GIM INTERNATIONAL, vol 26, n° 1, [01/01/2012], pp 28 - 31
DEVELOPPEMENT DURABLE, GESTION URBAINE, INDICATEUR SPATIAL, PLANIFICATION
URBAINE, SYSTEME D'INFORMATION GEOGRAPHIQUE, UTILISATEUR CIVIL
N° notice
A2012-007
Résumé d’auteur In the first decade of this millenium, spatial technologies have shifted from being used
only by specialised experts to being present on every one's laptop or cellular device. The
data held by special departments, offices and authorities has crossed over into the world
of the internet. Concurrent to this process, 'sustainable development' has moved from
theory into practice. In the Czech Republic, with its traditionally well-organised approach
to spatial planning, it was necessary for the pure, economic-based planning of the 1990s
to morph into strategic planning and city management. Along with new attitudes, this also
required a new breed of indicators - ones that would be easy for politicians and city
inhabitants to understand and visualise. Here, we examine one such case: the use of GIS
and three new indicators for spatial and strategic planning for the municipality of Hradec
Kralové, a city with 100 000 inhabitants, located in Bohemia.
Titre
Auteur(s)
Source
Mots clés
Measuring historical coastal change using GIS and the change polygon approach
SMITH (M.) et CROMLEY (R.)
ARCGIS, DETECTION DE CHANGEMENT, EROSION COTIERE, FORMAT TIFF, LITTORAL,
POLYGONE, POLYGONE DE THIESSEN, TRAIT DE COTE
N° notice
A2012-095
Résumé d’auteur This study compares two automated approaches, the transect-from-baseline technique
and a new change polygon method, for quantifying historical coastal change over time.
The study shows that the transect-from-baseline technique is complicated by choice of a
proper baseline as well as generating transects that intersect with each other rather than
with the nearest shoreline. The change polygon method captures the full spatial
difference between the positions of the two shorelines and average coastal change is the
defined as the ratio of the net area divided by the shoreline length. Although then change
polygon method is sensitive to the definition and measurement of shoreline length, the
results are more invariant to parameter changes than the transect-from-baseline method,
suggesting that the change polygon technique may be a more robust coastal change
method.
_______________________________________________________________________________________
Image acquisition
Titre
Auteur(s)
Source
Mots clés
Achieving big results from small sensors
AFLALO (A.) et YALON (D.)
AEROTRIANGULATION, COMPENSATION PAR FAISCEAUX, ORIENTATION EXTERNE,
PLATE-FORME LOGICIELLE, POINT DE LIAISON (IMAGERIE), PROCESSUS
PHOTOGRAMMETRIQUE
N° notice
A2012-037
Résumé d’éditeur Small and medium formats sensors present a number of challenges in photogrammetric
processing, not least their reliance on accurate external orientation data during image
capture. But, as Avi Aflalo and Dor Yalon explain, this need no longer present an
insurmountable obstacle for those tackling large, difficult projects calling for high
precision.
Titre
Auteur(s)
Source
Mots clés
Unmanned aerial vehicles: from toys to tools
GRUEN (A.)
GEOINFORMATICS, vol 15, n° 1, [01/01/2012], pp 14 - 16
DRONE, IMAGE AERIENNE, IMAGE AERIENNE A AXE VERTICAL, IMAGE AERIENNE
OBLIQUE
N° notice
A2012-028
Résumé d’auteur Unmanned aerial vehicles (UAVs) have recently attained great attention. This article
explains why this is so and describes the wide range of users and applications. But UAVs
also have a number of disadvantages, which have to be solved in the future in order to
establish a good transition from 'toys to tools'.
Titre
Auteur(s)
Source
Ultrawideband gated step frequency Ground-Penetrating Radar
OYAN (M.), HAMRAN (S.E.), HANSSEN (L.) et al.
IEEE TRANSACTIONS ON GEOSCIENCE & REMOTE SENSING, vol 50, n° 1, [01/01/2012], pp 212 220
Mots clés
BANDE SPECTRALE, CAPTEUR SPATIAL, MODULATION DE FREQUENCE, PROTOTYPE,
RADAR PENETRANT GPR
N° notice
A2012-034
Résumé d’auteur We describe a prototype ultrawideband radar. We show how the system was designed
and how the hardware was developed for the radar prototype. Waveform generation,
radar parameters, and signal processing for the stepped frequency waveform are
discussed. The radar operates from 500 MHz to 3 GHz with a nominal resolution of 6 cm
in air. The advantage of the stepped frequency approach over an impulse radar is better
matching between the transmitted waveform and the receiver. We use range gating to
improve the system dynamic range. The advantages are illustrated with laboratory
measurements and field measurements from glacial ice and permafrost in Svalbard,
showing penetration depths of 11 m. Antennas which do not require contact with the
ground were developed and used in the experiments.
Titre
Auteur(s)
Source
Mots clés
Imagery on call: Europe leads the way
ANONYME
IMAGE GOES, IMAGE SATELLITE, RISQUE ENVIRONNEMENTAL, RISQUE NATUREL,
SECURITE CIVILE
N° notice
A2012-115
Résumé d’auteur Imagine a fully-staffed, available 24/7 and ready to deliver satellite imagery within hours
of an emergency. A consortium has recently been appointed as the European Union's
exclusive provider of just such a service.
Image processing
Titre
Auteur(s)
The unmixing of atmospheric trace gases from hyperspectral satellite data
ADDABBO (P.), BISCEGLIE (M. DI) et GALDI (C.)
_______________________________________________________________________________________
Source
Mots clés
IEEE TRANSACTIONS ON GEOSCIENCE & REMOTE SENSING, vol 50, n° 1, [01/01/2012], pp GAZ, IMAGE HYPERSPECTRALE, OZONE, OZONE MONITORING INSTRUMENT, SPECTRAL
UNMIXING CLASSIFICATION
N° notice
A2012-036
Résumé d’auteur A new approach for the retrieval of the vertical column concentrations of trace gases,
from hyperspectral satellite reflectances, is presented. The investigation moves from the
general rationale of independent component analysis, but the constraint of perfect
independence among sources is replaced by a minimum dependence concept that
proves more reasonable for the application at hand. The unmixing of the gas spectra and
their concentrations is achieved from linear mixtures obtained from the logarithm of the
spectral reflectance. After a proper preprocessing stage aimed at reducing major residual
dependences caused by atmospheric scattering, trace-gas retrieval is carried out through
a minimization of a statistical cost function, subject to the physical constraint that the
resulting spectra must be nonnegative. The experimental analysis relies on the retrieval
of sulfur dioxide during volcanic emissions using data from the National Aeronautics and
Space Administration Ozone Monitoring Instrument. To validate the procedure, reference
reflectance spectra having a known profile of sulfur dioxide are generated with the
MODerate resolution atmospheric TRANsmission software, and the retrieved
concentration is compared with the theoretical one. Performance in the presence of shot
and detector noise has also been analyzed starting from pure simulated spectral
reflectances.
Titre
Auteur(s)
Source
Mots clés
A genetic fuzzy-rule-based classifier for land cover classification from
hyperspectral imagery
STAVRAKOUDIS (D.), GALIDAKI (G.), GITAS (I.) et al.
CLASSIFICATION PAR ALGORITHME GENETIQUE, GENETIC FUZZY-RULE-BASED
CLASSIFICATION, IMAGE EO1-HYPERION, IMAGE HYPERSPECTRALE, OCCUPATION DU
SOL
N° notice
A2012-032
Résumé d’auteur This paper proposes the use of a genetic fuzzy-rule-based classification system for land
cover classification from hyperspectral images. The proposed classifier, namely, Feature
Selective Linguistic Classifier, is constructed through a three-stage learning process. The
first stage produces a preliminary fuzzy rule base in an iterative fashion. During this
stage, a local feature selection scheme is employed, designed to guide the genetic
evolution, through the evaluation of deterministic information about the relevance of each
feature with respect to its classification ability. The structure of the model is then
simplified in a subsequent post-processing stage. The performance of the classifier is
finally optimized through a genetic tuning stage. An extensive comparative analysis,
using an Earth Observing-1 Hyperion satellite image, highlights the quality advantages of
the proposed system, when compared with non-fuzzy classifiers, commonly employed in
hyperspectral classification tasks.
Titre
Auteur(s)
Source
Mots clés
A simple and robust feature point matching algorithm based on restricted spatial
order constraints for aerial image registration
LIU (Z.), AN (J.) et JING (Y.)
APPARIEMENT DE GRAPHES, APPARIEMENT DE POINTS, IMAGE AERIENNE, IMAGE
OPTIQUE, IMAGE RADAR MOIREE, PROGRAMMATION PAR CONTRAINTES,
SUPERPOSITION D'IMAGES, VALEUR ABERRANTE
N° notice
A2012-046
Résumé d’auteur Accurate point matching is a critical and challenging process in feature-based image
registration. In this paper, a simple and robust feature point matching algorithm, called
Restricted Spatial Order Constraints (RSOC), is proposed to remove outliers for
registering aerial images with monotonous backgrounds, similar patterns, low overlapping
areas, and large affine transformation. In RSOC, both local structure and global
information are considered. Based on adjacent spatial order, an affine invariant descriptor
is defined, and point matching is formulated as an optimization problem. A graph
matching method is used to solve it and yields two matched graphs with a minimum
global transformation error. In order to eliminate dubious matches, a filtering strategy is
designed. The strategy integrates two-way spatial order constraints and two decision
_______________________________________________________________________________________
criteria restrictions, i.e., the stability and accuracy of transformation error. Twenty-nine
pairs of optical and Synthetic Aperture Radar (SAR) aerial images are utilized to evaluate
the performance. Compared with RANdom SAmple Consensus (RANSAC), Graph
Transformation Matching (GTM), and Spatial Order Constraints (SOC), RSOC obtained
the highest precision and stability.
Titre
Auteur(s)
Source
Mots clés
An edge-oriented approach to thematic map error assessment
SWEENEY (S.) et EVANS (T.)
GÉOCARTO INTERNATIONAL, vol 27, n° 1, [01/02/2012], pp 31 - 56
CONTOUR, ERREUR DE CLASSIFICATION, IMAGE LANDSAT-TM, OCCUPATION DU SOL,
PIXEL, PRECISION DE LA CLASSIFICATION
N° notice
A2012-104
Résumé d'auteur The objective of this analysis is to develop a method of classification error assessment
that can contribute to techniques designed to evaluate change products with an emphasis
on edge locations in landscapes. Reference land-cover data were developed within 10
randomly sampled regions across the study site, approximately 9 km2 each. Sample
pixels were partitioned and allocated among two domain categories, interior and edge.
The assignment of pixels to domain categories was based on neighbourhood
heterogeneity. Classification error was assessed within domain categories on a pixel-bypixel basis, evaluating agreement between map values and majority land cover. To
demonstrate the methodology, we present summary results for this technique applied to a
land-cover classification of south-central Indiana. Omission error was less than 8.3%
within interior domains and from 25.8% to 36.4% in the edge. Commission error was
below 26.7% within the interior domains and ranged from 13.9 to 74.6% in the edge
domains.
Titre
Auteur(s)
Source
Mots clés
Coupled nonnegative matrix factorization unmixing for hyperspectral and
multispectral data fusion
YOKOYA (N.), YAIRI (T.) et IWASAKI (A.)
FUSION D'IMAGES, IMAGE HYPERSPECTRALE, IMAGE MULTIBANDE, LINEAR UNMIXING,
MATRICE
N° notice
A2012-047
Résumé d’auteur Coupled nonnegative matrix factorization (CNMF) unmixing is proposed for the fusion of
low-spatial-resolution hyperspectral and high-spatial-resolution multispectral data to
produce fused data with high spatial and spectral resolutions. Both hyperspectral and
multispectral data are alternately unmixed into end member and abundance matrices by
the CNMF algorithm based on a linear spectral mixture model. Sensor observation
models that relate the two data are built into the initialization matrix of each NMF
unmixing procedure. This algorithm is physically straightforward and easy to implement
owing to its simple update rules. Simulations with various image data sets demonstrate
that the CNMF algorithm can produce high-quality fused data both in terms of spatial and
spectral domains, which contributes to the accurate identification and classification of
materials observed at a high spatial resolution.
Titre
Auteur(s)
Source
Development of a network-based method for unmixing of hyperspectral data
KARATHANASSI (V.), SYKAS (D.) et TOPOUZELIS (K.)
Mots clés
DISTANCE EUCLIDIENNE, IMAGE HYPERSPECTRALE, SPECTRAL UNMIXING
CLASSIFICATION
N° notice
A2012-099
Résumé d’auteur This paper presents a new nonlinear unmixing method. Based on relative distances which
imply nonlinearity, the method introduces the “fractional distance” as a key variable that
quantifies interactions between pixels and endmembers. Relationships between fractional
distances and abundance fractions are built through networks. Because an equal spectral
mixture of ground spectral classes present on the surface sensed is likely impossible, the
proposed method, due to its mathematical concept, reveals unknown endmembers.
Three versions of the method have been developed: the non-constrained, the sum-toone, and the fully constrained versions. Evaluation of the method using synthetic and real
data showed that the method is robust with clear and interpretable results and provides
reliable abundance fractions, particularly the sum-to-one and the fully constrained
_______________________________________________________________________________________
versions of the method. The new unmixing method has also been compared with the fully
constrained least squares method.
Titre
Auteur(s)
Source
Hyperspectral unmixing based on mixtures of Dirichlet components
NASCIMENTO (J.) et BIOUCAS-DIAS (J.)
Mots clés
CLASSIFICATION NON DIRIGEE, DONNEES LIDAR, IMAGE HYPERSPECTRALE, PROBLEME
DE DIRICHLET, SPECTRAL UNMIXING CLASSIFICATION
N° notice
A2012-100
Résumé d’auteur This paper introduces a new unsupervised hyperspectral unmixing method conceived to
linear but highly mixed hyperspectral data sets, in which the simplex of minimum volume,
usually estimated by the purely geometrically based algorithms, is far way from the true
simplex associated with the endmembers. The proposed method, an extension of our
previous studies, resorts to the statistical framework. The abundance fraction prior is a
mixture of Dirichlet densities, thus automatically enforcing the constraints on the
abundance fractions imposed by the acquisition process, namely, nonnegativity and sumto-one. A cyclic minimization algorithm is developed where the following are observed: 1)
The number of Dirichlet modes is inferred based on the minimum description length
principle; 2) a generalized expectation maximization algorithm is derived to infer the
model parameters; and 3) a sequence of augmented Lagrangian-based optimizations is
used to compute the signatures of the endmembers. Experiments on simulated and real
data are presented to show the effectiveness of the proposed algorithm in unmixing
problems beyond the reach of the geometrically based state-of-the-art competitors.
Titre
Auteur(s)
Source
Mots clés
Automatic classification of building types in 3D city models: Using SVMs for
semantic enrichment of low resolution building data
HENN (A.), ROMER (C.), GROGER (G.) et PLUMER (L.)
APPRENTISSAGE AUTOMATIQUE, ATTRIBUT SEMANTIQUE, BATI, CLASSIFICATION
AUTOMATIQUE, CLASSIFICATION PAR MACHINE A VECTEURS DE SUPPORT, IMAGE A
BASSE RESOLUTION, MODELE 3D DE L'ESPACE URBAIN
N° notice
A2012-089
Résumé d’auteur This article presents a classifier based on Support Vector Machines (SVMs), an advanced
machine learning method for semantic enrichment of coarse 3D city models by deriving
the building type. The information on the building type (detached building, terraced
building, etc.) is essential for a variety of relevant applications of 3D city models like
spatial marketing, real estate management and marketing, and for visualization. The
derivation of the building type from coarse data (mainly 2D footprints, building heights
and functions) seems impossible at first sight. However it succeeds by incorporating the
spatial context of a building. Since the input data can be derived easily and at very low
cost, this method is widely applicable. Nevertheless, as with all supervised learning
algorithms, obtaining labelled training data is very time-consuming. Herewith, we provide
a method which uses outlier detection and clustering methods to support users in
efficiently and rapidly obtaining adequate training data.
Titre
Auteur(s)
Source
Mots clés
Efficient parallel algorithm for pixel classification in remote sensing imagery
MAULIK (U.) et SARKAR (A.)
ANALYSE DE GROUPEMENT, CLASSIFICATION BARYCENTRIQUE, CLASSIFICATION
DIRIGEE, IMAGE IRS, IMAGE SPOT, PIXEL, TRAITEMENT PARALLELE
N° notice
A2012-094
Résumé d'auteur An important approach for image classification is the clustering of pixels in the spectral
domain. Fast detection of different land cover regions or clusters of arbitrarily varying
shapes and sizes in satellite images presents a challenging task. In this article, an
efficient scalable parallel clustering technique of multi-spectral remote sensing imagery
using a recently developed point symmetry-based distance norm is proposed. The
proposed distributed computing time efficient point symmetry based K-Means technique
is able to correctly identify presence of overlapping clusters of any arbitrary shape and
size, whether they are intra-symmetrical or inter-symmetrical in nature. A Kd-tree based
approximate nearest neighbor searching technique is used as a speedup strategy for
computing the point symmetry based distance. Superiority of this new parallel
implementation with the novel two-phase speedup strategy over existing parallel K_______________________________________________________________________________________
Means clustering algorithm, is demonstrated both quantitatively and in computing time,
on two SPOT and Indian Remote Sensing satellite images, as even K-Means algorithm
fails to detect the symmetry in clusters. Different land cover regions, classified by the
algorithms for both images, are also compared with the available ground truth
information. The statistical analysis is also performed to establish its significance to
classify both satellite images and numeric remote sensing data sets, described in terms
of feature vectors.
Lasergrammetry
Titre
Auteur(s)
Source
Automatic stem mapping using single-scan terrestrial laser scanning
LIANG (X.), LITKEY (P.), HYYPPA (J.) et al.
Mots clés
CONIFERE, DONNEES LIDAR, DONNEES LOCALISEES 3D, FORET, TELEMETRIE LASER
TERRESTRE, TRONC
N° notice
A2012-050
Résumé d’auteur The demand for detailed ground reference data in quantitative forest inventories is
growing rapidly, e.g., to improve the calibration of the developed models of airbornelaser-scanning-based inventories. The application of terrestrial laser scanning (TLS) in
the forest has shown great potential for improving the accuracy and efficiency of field
data collection. This paper presents a fully automatic stem-mapping algorithm using
single-scan TLS data for collecting individual tree information from forest plots. In this
method, the stem points are identified by the spatial distribution properties of the laser
points, the stem model is built up of a series of cylinders, and the location of the stem is
estimated by the model. The experiment was performed on nine plots with 10-m radius.
The stem-location maps measured in the field by traditional methods were used as the
ground truth. The overall stem-mapping accuracy was 73%. The result shows that, in a
relatively dense managed forest, the majority of stems can be located by the automatic
algorithm. The proposed method is a general solution for stem locating where particular
plot knowledge and data format are not required.
Titre
Auteur(s)
Source
Mots clés
Extraction of building roof contours from LiDAR data using a Markov-random-fieldbased approach
DOS SANTOS GALVANIN (E.) et DAL POZ (A.)
ALGORITHME DU RECUIT SIMULE, BATI, CHAMP DE MARKOV, DETECTION DE CONTOUR,
DONNEES LIDAR, DONNEES LOCALISEES 3D, EXTRACTION AUTOMATIQUE, TOIT
N° notice
A2012-101
Résumé d’auteur This paper proposes a method for the automatic extraction of building roof contours from
a digital surface model (DSM) by regularizing light detection and ranging (LiDAR) data.
The method uses two steps. First, to detect aboveground objects (buildings, trees, etc.),
the DSM is segmented through a recursive splitting technique followed by a regionmerging process. Vectorization and polygonization are used to obtain polyline
representations of the detected aboveground objects. Second, building roof contours are
identified from among the aboveground objects by optimizing a Markov-random-fieldbased energy function that embodies roof contour attributes and spatial constraints. The
optimal configuration of building roof contours is found by minimizing the energy function
using a simulated annealing algorithm. Experiments carried out with the LiDAR-based
DSM show that the proposed method works properly, as it provides roof contour
information with approximately 90% shape accuracy and no verified false positives.
Titre
Auteur(s)
Source
Mots clés
Digital measurements with 3D laser scanner: German scanning project
RECHENBACH (J.)
N° notice
A2012-055
BATIMENT, DONNEES LIDAR, DONNEES LOCALISEES 3D, LIDAR, TELEMETRIE LASER
TERRESTRE
_______________________________________________________________________________________
Résumé d’éditeur If three-dimensional measurement of structures has been very complicated, expensive
and error-prone up until now, then data collection with the latest generation of 3D laser
scanners is now easy, accurate and rapid.
Navigation and positioning
Titre
Auteur(s)
Source
Mots clés
Galileo's surveying potential: E5 pseudorange precision
COLOMINA (I.), MIRANDA (C.), PARES (M.) et al.
GPS WORLD, vol 23, n° 3, [01/03/2012], pp 18 - 33
POSITIONNEMENT PAR GALILEO, PRECISION DU POSITIONNEMENT, PSEUDO-DISTANCE,
SIGNAL GALILEO
N° notice
A2012-112
Résumé d’auteur New Galileo signals have great potential for pseudorange-based surveying and mapping
in both optimal open-sky conditions and suboptimal under-canopy environments. This
article reviews the main features of Galileo's E5 AltBOC and E1 CBOC signals, describes
generation of realistic E and E1 pseudo-ranges with or without multipath sources, and
presents anticipated horizontal positioning accuracy results, ranging from 4 centimeters
(open-sky) to 14 centimeters (under canopy) for E5/E1.
Titre
Auteur(s)
Source
Mots clés
Mapping the indoor world: towards crowdsourcing geographic information about
indoor spaces
GOETZ (M.) et ZIPF (A.)
CARTOGRAPHIE D'INTERIEUR, EXTERNALISATION OUVERTE, INFORMATION
GEOGRAPHIQUE VOLONTAIRE, OPENSTREETMAP, POSITIONNEMENT EN INTERIEUR
N° notice
A2012-057
Résumé d’auteur The availability of mobile devices for all has boosted the demand for indoor locationbased services such as indoor routing or indoor navigation. Both researchers and
companies are trying to adapt well-known outdoor solutions to the requirements of indoor
spaces. Crowdsourced geographic information is already a promising new data source
for outdoor applications. A logical next step would be to apply this novel paradigm to the
indoor world. The authors propose and discuss a new model that extends the scope of
Volunteered Geographic Information (VGI) communities - essentially OpenStreetMap towards indoor spaces. This enables the open collection and usage of indoor information
such as emergency navigation in a hotel or personal navigation at the airport. Hence,
large-scale availability of indoor VGI would have a positive social impact and add value in
many different areas.
Titre
Auteur(s)
Source
Mots clés
N° notice
Résumé d’éditeur
The sky is on the move: the benefits of Galileo
JURRY DE LA MAR (D.)
ENJEU, GALILEO
A2012-056
Admittedly, in competition with the American GPS and the Russian Glonass system,
prestige also plays a role for the European Galileo satellite navigation system. But above
all, the continental economy and the people of the 'old world' will gain from the five billion
Euro cost - and with this the most important and largest high tech project in Europe.
Radar image processing
Titre
Auteur(s)
Source
Long-term consecutive DInSAR for volume change estimation of land deformation
SUMANTYO (S.), SHIMADA (M.), MATHIEU (P.) et al.
Mots clés
ANALYSE DIACHRONIQUE, DEFORMATION DE LA CROUTE TERRESTRE, IMAGE ALOSPALSAR, IMAGE JERS, INTERFEROMETRIE DIFFERENTIELLE, SUBSIDENCE, VOLUME
(GRANDEUR)
N° notice
A2012-035
_______________________________________________________________________________________
Résumé d'auteur In this paper, the long-term consecutive differential interferometric synthetic aperture
radar (SAR) technique is used to measure the volume change during land deformation.
This technique was used to investigate the subsidence of Bandung city, Indonesia, by
assessing the data from two Japanese L-band spaceborne SARs (Japanese Earth
Resources Satellite 1 SAR and Advanced Land Observation Satellite Phased Array type
L-band Synthetic Aperture Radar) during the periods of 1993-1997 and 2007-2010. The
results are confirmed using GPS observation data, ground survey data, local statistics,
ground water level trend data, and the geological formation of the study area. The
obtained results reveal a close correlation between the subsidence measurements and
changes in the ground water level due to water pumping, population growth, industry
growth, and urbanization of the study area.
Titre
Auteur(s)
Source
Mots clés
Laplacian eigenmaps-based polarimetric dimensionality reduction for SAR image
classification
TU (S.T.), CHEN (J.H.), YANG (W.) et al.
IMAGE POLSAR, LAPLACIAN EIGENMAP CLASSIFICATION, OCCUPATION DU SOL,
POLARIMETRIE RADAR
N° notice
A2012-033
Résumé d’auteur In this paper, we propose a novel scheme of polarimetric synthetic aperture radar
(PolSAR) image classification. We apply Laplacian eigenmaps (LE), a nonlinear
dimensionality reduction (NDR) technique, to a high-dimensional polarimetric feature
representation for PolSAR land-cover classification. A wide variety of polarimetric
signatures are chosen to construct a high-dimensional polarimetric manifold which can be
mapped into the most compact low-dimensional structure by manifold-based
dimensionality reduction techniques. This NDR technique is employed to obtain a lowdimensional intrinsic feature vector by the LE algorithm, which is beneficial to PolSAR
land-cover classification owing to its local preserving property. The effectiveness of our
PolSAR land-cover classification scheme with LE intrinsic feature vector is demonstrated
with the RadarSat-2 C-band PolSAR data set and the 38th Research Institute of China
Electronics Technology Group Corporation X-band PolInSAR data set. The performance
of our method is measured by the separability in the feature space and the accuracy of
classification. Comparisons on the feature space show that the LE intrinsic feature vector
is more separable than different original feature vectors. Our LE intrinsic feature vector
also improves the classification accuracy.
Titre
Auteur(s)
Source
Filtering and segmentation of polarimetric SAR data based on binary partition trees
ALONSO-GONZALEZ (A.), LOPEZ-MARTINEZ (C.) et SALEMBIER (P.)
Mots clés
ARBRE-B, DONNEES POLARIMETRIQUES, FILTRE DE DECHATOIEMENT, POLARIMETRIE
RADAR, SEGMENTATION D'IMAGE
N° notice
A2012-048
Résumé d’auteur In this paper, we propose the use of binary partition trees (BPT) to introduce a novel
region-based and multi-scale polarimetric SAR (PolSAR) data representation. The BPT
structure represents homogeneous regions in the data at different detail levels. The
construction process of the BPT is based, firstly, on a region model able to represent the
homogeneous areas, and, secondly, on a dissimilarity measure in order to identify similar
areas and define the merging sequence. Depending on the final application, a BPT
pruning strategy needs to be introduced. In this paper, we focus on the application of BPT
PolSAR data representation for speckle noise filtering and data segmentation on the
basis of the Gaussian hypothesis, where the average covariance or coherency matrices
are considered as a region model. We introduce and quantitatively analyze different
dissimilarity measures. In this case, and with the objective to be sensitive to the complete
polarimetric information under the Gaussian hypothesis, dissimilarity measures
considering the complete covariance or coherency matrices are employed. When
confronted to PolSAR speckle filtering, two pruning strategies are detailed and evaluated.
As presented, the BPT PolSAR speckle filter defined filters data according to the
complete polarimetric information. As shown, this novel filtering approach is able to
achieve very strong filtering while preserving the spatial resolution and the polarimetric
information. Finally, the BPT representation structure is employed for high spatial
_______________________________________________________________________________________
resolution image segmentation applied to coastline detection. The analyses detailed in
this work are based on simulated, as well as on real PolSAR data acquired by the ESAR
system of DLR and the RADARSAT-2 system.
Titre
Auteur(s)
Source
Mots clés
Usefulness of synthetic aperture radar (SAR) interferometry for digital elevation
model (DEM) generation and estimation of land surface displacement in Jharia coal
field area
BHATTACHARYA (A.), ARORA (M.) et SHARMA (M.)
APPARIEMENT DE FORMES, EFFONDREMENT DE TERRAIN, IMAGE RADAR MOIREE,
INTERFEROMETRIE DIFFERENTIELLE, INTERFEROMETRIE PAR RADAR A ANTENNE
SYNTHETIQUE, MINE DE CHARBON, MODELE NUMERIQUE DE SURFACE, MOUVEMENT DE
TERRAIN
N° notice
A2012-103
Résumé d'auteur Land surface displacement is a phenomenon of ground movement, which may occur due
to various reasons including unplanned mining. The quantification of land surface
displacement through conventional field surveys is based on sparingly distributed point
data, which may be insufficient for many applications. A detailed spatial and temporal
monitoring of land surface displacements through remote sensing-based synthetic
aperture radar (SAR) interferometry may be valuable. Over the last two decades,
differential SAR interferometry (DInSAR) has been effectively used globally for the
estimation of spatial land surface displacements caused due to natural and man-made
hazards. However, it has not gained momentum in India, where occurrences of natural
and man-made hazards are a common phenomenon. In this article, preliminary results
from DInSAR to measure land surface displacement in Jharia coal fields have been
presented. DInSAR results effectively identified the land surface displacement due to
several mining activities in the region during a one-month period.
Titre
Auteur(s)
Source
Markov Chain CFAR detection for polarimetric data using data fusion
FEI (C.), LIU (T.), LAMPROPOULOS (G.) et al.
Mots clés
CHAINE DE MARKOV, DONNEES POLARIMETRIQUES, FUSION D'IMAGES, IMAGE RADAR
MOIREE, IMAGE RADARSAT, POLARIMETRIE RADAR
N° notice
A2012-044
Résumé d’auteur This paper proposes a new Markov-chain-based constant false alarm rate (CFAR)
detector for polarimetric data using low-level data fusion and high-level decision fusion.
The Markov-chain-based CFAR detector extends traditional probability density function
(pdf) based CFAR detection to first-order Markov chain model by considering both
correlation between neighboring pixels and pdf information in CFAR detection. With the
additional correlation information, the proposed approach results in advancing the
performance of conventional CFAR detectors. Moreover, to take advantage of full
polarizations of polarimetric data, various data fusion methods are considered to improve
detection performance, including polarimetric transformation, principal component
analysis, and decision fusion. Our experimental results confirm the superiority of the new
Markov chain polarimetric CFAR detector over conventional pdf-based CFAR detectors.
Titre
Auteur(s)
Source
A nonlocal SAR image denoising algorithm based on LLMMSE wavelet shrinkage
PARRILLI (S.), PODERICO (M.), ANGELINO (C.) et al.
Mots clés
FILTRE DE DECHATOIEMENT, FILTRE DE WIENER, IMAGE RADAR MOIREE,
TRANSFORMATION EN ONDELETTES
N° notice
A2012-049
Résumé d’auteur We propose a novel despeckling algorithm for synthetic aperture radar (SAR) images
based on the concepts of nonlocal filtering and wavelet-domain shrinkage. It follows the
structure of the block-matching 3-D algorithm, recently proposed for additive white
Gaussian noise denoising, but modifies its major processing steps in order to take into
account the peculiarities of SAR images. A probabilistic similarity measure is used for the
block-matching step, while the wavelet shrinkage is developed using an additive signaldependent noise model and looking for the optimum local linear minimum-mean-squareerror estimator in the wavelet domain. The proposed technique compares favorably w.r.t.
_______________________________________________________________________________________
several state-of-the-art reference techniques, with better results both in terms of signal-tonoise ratio (on simulated speckled images) and of perceived image quality.
Remote sensing applications
Titre
Auteur(s)
Source
Mots clés
Characterization of Arctic sea ice thickness using high-resolution spaceborne
polarimetric SAR data
KIM (J.W.), KIM (D.J.) et HWANG (B.J.)
IEEE TRANSACTIONS ON GEOSCIENCE & REMOTE SENSING, vol 50, n° 1, [01/01/2012], pp 13 - 22
ARCTIQUE (OCEAN), BANDE C, BANDE X, DONNEES POLARIMETRIQUES, EPAISSEUR DE
LA GLACE, GLACE DE MER, IMAGE RADARSAT, IMAGE TERRASAR-X, POLARIMETRIE
RADAR, POLARISATION, POLARISATION CROISEE, TELEDETECTION EN
HYPERFREQUENCE
N° notice
A2012-030
Résumé d’auteur In this paper, we have investigated the relationship between the depolarization effects
and the wintertime sea ice thickness in the landfast ice region where smooth thick firstyear ice (FYI) and deformed old ice coexisted by using C- and X-band spaceborne
polarimetric synthetic aperture radar (SAR) data (RADARSAT-2 and TerraSAR-X). We
have found a strong correlation between the in situ sea ice thickness and the SARderived depolarization factors (copolarized correlation and cross-polarized ratio). The
observed relationships have demonstrated not only a categorical difference between FYI
and multiyear ice (MYI) but also a one-to-one continuity in the scatter plots, rather than
being clustered. It clearly shows that the observed correlations are not merely from the
categorical difference in scattering mechanism between FYI and MYI and that there might
exist a one-to-one relationship between thickness and depolarization factors at least in
our deformed ice case. This suggests that depolarization factors could be effective SAR
parameters in the estimation of wintertime sea ice thickness. Numerical model
simulations explained some portions of the correlation by employing multiple scattering
on the sea ice surface and volume scattering within the low-density subsurface layer.
Titre
Auteur(s)
Source
Mots clés
Joint processing of Landsat and ALOS-PALSAR data for forest mapping and
monitoring
LEHMANN (E.), CACCETTA (P.), ZHOU (Z.S.) et al.
IEEE TRANSACTIONS ON GEOSCIENCE & REMOTE SENSING, vol 50, n° 1, [01/01/2012], pp 55 - 67
ANALYSE DISCRIMINANTE, CARTE DE LA VEGETATION, FORET EQUATORIALE, FUSION
D'IMAGES, IMAGE ALOS-PALSAR, IMAGE LANDSAT-TM, IMAGE OPTIQUE, IMAGE RADAR,
SURVEILLANCE FORESTIERE
N° notice
A2012-031
Résumé d’auteur Recent technological advances in the field of radar remote sensing have allowed the
deployment of an increasing number of new satellite sensors. These provide an important
source of Earth observation data, which add to the currently existing optical data sets. In
parallel, the development of robust methods for global forest monitoring and mapping is
becoming increasingly important. As a consequence, there is significant interest in the
development of global monitoring systems that are able to take advantage of the potential
synergies and complementary nature of optical and radar data. This paper proposes an
approach for the combined processing of Landsat and ALOS-PALSAR data for the
purpose of forest mapping and monitoring. This is achieved by incorporating the PALSAR
data into an existing operational Landsat-based processing system. Using a directed
discriminant technique, a probability map of forest presence/absence is first generated
from the PALSAR imagery. This SAR classification data is then combined with a time
series of similar Landsat-based maps within a Bayesian multitemporal processing
framework, leading to the production of a time series of joint radar-optical maps of forest
extents. This approach is applied and evaluated over a pilot study area in northeastern
Tasmania, Australia. Experimental outcomes of the proposed joint processing framework
are provided, demonstrating its potential for the integration of different types of remote
sensing data for forest monitoring purposes.
_______________________________________________________________________________________
Signal processing
Titre
Auteur(s)
Source
Mots clés
N° notice
Résumé d’auteur
Interference & Einstein: GNSS update
LEKKERKERK (H.)
Titre
Auteur(s)
Source
Mots clés
Know your enemy: signal characteristics of civil GPS jammers
MITCH (R.), DOUGHERTY (R.), PSIAKI (M.) et al.
GPS WORLD, vol 23, n° 1, [01/01/2012], pp 64 - 71
ERUPTION SOLAIRE, INTERFERENCE, NAVIGATION, SIGNAL GNSS
A2012-029
Some of you may have heard about the experiment at CERN that seems to prove that
things can actually go faster than light, something that Einstein said was impossible. So
what does a physical experiment have to do with a GNSS update you may ask.
ANALYSE COMPARATIVE, APPAREIL PORTABLE, BROUILLAGE, POSITIONNEMENT PAR
GPS
N° notice
A2012-020
Résumé d’auteur GPS is at war. It is a major asset for United States and allied military forces in a number
of operating theaters around the world in both declared and undeclared conflicts. But
GPS is at war on the domestic front, too at war against a proliferation of jamming
equipment being marketed to cause deliberate interference to GPS signals to prevent
GPS receivers from computing positions to be locally stored or relayed via tracking
networks. There have been many notable examples of deliberate jamming of GPS
receivers. Many more likely go undetected each day. In 2009, outages of a Federal
Aviation Administration reference receiver at Newark Liberty International Airport close to
the New Jersey Turnpike were traced to a $33,200 milliwatt GPS jammer in a truck that
passed the airport each day. The driver was reportedly arrested and charged. In July
2010, two truck thieves in Britain were jailed for 16 years. They used GPS jammers to
prevent the trucks from being tracked after the thefts. And in Germany, some truck
drivers have been using jammers to evade the country's GPS-based road-toll system.
The U.S. and some foreign governments have enacted laws to prohibit the importation,
marketing, sale or operation of these so-called personal privacy devices. Nevertheless, a
certain number of jammers are in the hands of individuals around the world and they
continue to be available from manufacturers and suppliers in certain countries. So, GPS
jamming is a continuing threat both at home and abroad and a detailed understanding of
how the available jammers work is necessary to judge their effectiveness and limitations.
This information will also help in developing countermeasures that could be incorporated
into GPS receivers to limit the impact of jammers. Jammers constitute an enemy force,
and as the Chinese General Sun Tzu stated in the Art of War more than 2,000 years ago,
battles will be won by knowing your enemy. […] In this month's column, a team of
researchers from Cornell University and the University of Texas at Austin reports on their
analyses of the signal properties of 18 commercially available GPS jammers. The enemy
has been exposed.
Titre
Auteur(s)
Source
Mots clés
N° notice
Résumé d’auteur
Straight talk on anti-spoofing: securing the future of PNT
WESSON (K.), SHEPARD (D.) et HUMPHREYS (T.)
GPS WORLD, vol 23, n° 1, [01/01/2012], pp 32 - 62
Titre
Auteur(s)
Source
Mots clés
N° notice
GNSS antennas and humans: a study of their interactions
BANCROFT (J.), RENAUDIN (V.), MORRISON (A.) et LACHAPELLE (G.)
GPS WORLD, vol 23, n° 2, [01/02/2012], pp 60 - 66
ANTI-LEURRAGE
A2012-019
Disruption created by intentional generation of fake GPS signals could have serious
economic consequences. This article discusses how typical civil GPS receivers respond
to an advanced civil GPS spoofing attack, and four techniques to counter such attacks:
spread-spectrum security codes, navigation message authentication, dual-receiver
correlation of military signals, and vestigial signal defense. Unfortunately, any kind of antispoofing, however necessary, is a tough sell.
ANTENNE GNSS, PROPAGATION DU SIGNAL
A2012-054
_______________________________________________________________________________________
Résumé d’éditeur GPS is virtually ubiquitous with more than 400 million units estimated to be in use in the
United States alone. Some of these units are standalone devices such as those used in
surveying and timing applications and those used for vehicle navigation or tracking with
permanent or temporary mountings. However, the majority of the units are integrated into
cellular telephones, tablet computers, personal digital assistants, watches, cameras, and
other devices, which are designed to operate in close contact with the human body. We
even now have GPS shoes! It is well known that the performance of the antenna of a
radio receiver can be affected when it is used in close proximity to the human body. So,
when we use a handheld GPS receiver or wear a GPS watch, or put a GPS-equipped
cellular telephone up to our ear, are there any effects on the operation of the receiver? It
turns out that there are four major effects that can change the performance of a GPS (or
other GNSS) receiver antenna when placed near or on the human body. […] All these
factors need to be taken into consideration when a manufacturer is designing a GPS unit
to be operated in close proximity to a human body. Trade-offs might be possible and
certains designs may make the antenna less likely to interact with its surroundings. But
how does one go about assessing the antenna's performance in a repeatable and
quantifiable way? […] A team of researchers from the University of Calgary report n tests
conducted on two different types of GPS antennas operated in the vicinity of a human
phantom - an artificial body with similar electromagnetic properties as that of a real
human.
Titre
Auteur(s)
Source
Comparison of ray-tracing packages for troposphere delays
NAFISI (V.), URQUHART (L.), SANTOS (M.C.) et al.
Mots clés
ERREUR SYSTEMATIQUE, LANCER DE RAYONS, MODELE ATMOSPHERIQUE,
PROPAGATION TROPOSPHERIQUE, REFRACTION ATMOSPHERIQUE
N° notice
A2012-045
Résumé d’auteur A comparison campaign to evaluate and compare troposphere delays from different raytracing software was carried out under the umbrella of the International Association of
Geodesy Working Group 4.3.3 in the first half of 2010 with five institutions participating:
the GFZ German Research Centre for Geosciences (GFZ), the Groupe de Recherche de
Geodesie Spatiale, the National Institute of Information and Communications Technology
(NICT), the University of New Brunswick, and the Institute of Geodesy and Geophysics of
the Vienna University of Technology. High-resolution data from the operational analysis
of the European Centre for Medium-Range Weather Forecasts (ECMWF) for stations
Tsukuba (Japan) and Wettzell (Germany) were provided to the participants of the
comparison campaign. The data consisted of geopotential differences with respect to
mean sea level, temperature, and specific humidity, all at isobaric levels. Additionally,
information about the geoid undulations was provided, and the participants computed the
ray-traced total delays for 5° elevation angle and every degree in azimuth. In general, we
find good agreement between the ray-traced slant factors from the different solutions at
5° elevation if determined from the same pressure level data of the ECMWF. Standard
deviations and biases are at the 1-cm level (or significantly better for some
combinations). Some of these discrepancies are due to differences in the algorithms and
the interpolation approaches. If compared with slant factors determined from ECMWF
native model level data, the biases can be significantly larger.
Titre
Auteur(s)
Source
Mots clés
N° notice
Résumé d’auteur
Patch antennas for the new GNSS: better reception in a changing world
PANTHER (G.)
GPS WORLD, vol 23, n° 2, [01/02/2012], pp 52 - 58
LARGEUR DE BANDE, RECEPTEUR GNSS
A2012-053
Small ceramic patch elements offer nearly perfect single-frequency receive characteristics
and have become the standard for GPS L1 antennas. However, the new generation of
GNSS receivers now being introduced track many satellites in multiple constellations. Are
these narrow-band devices up to the task for wider bandwidths?
_______________________________________________________________________________________
Spatial analysis
Titre
Auteur(s)
Source
Mots clés
Fuzzy analysis for modeling regional delineation and development: The case of the
Sardinian mining geopark
MANCA (G.) et CURTIN (K.)
ANALYSE DE GROUPEMENT, LOGIQUE FLOUE, REGION GEOGRAPHIQUE,
REGIONALISATION
N° notice
A2012-098
Résumé d’auteur Although defining geographic regions for analysis can be a complex exercise, involving
both physical and human geographic perspectives, employing both qualitative and
quantitative data, and integrating a wide range of social, economic, and political factors, it
is frequently a necessary exercise in the pursuit of regional development. This article
presents a method for modeling and delineating regions with fuzzy analysis for the
purpose of regional development. A review of the literature regarding fuzzy analysis is
provided, which demonstrates that this method is both novel and necessary. An
application of this method is described in the context of the Sardinian Geopark. The fuzzy
clustering analysis demonstrates how combinations of factors can inform decisions
regarding where and how to initiate or continue regional development efforts.
Suggestions for improvements and extensions to this process are provided.
Titre
Auteur(s)
Source
Mots clés
A longitudinal study of malaria associated with deforestation in Sonitpur district of
Assam, India
NATH (M.), BORA (A.), TALUKDAR (P.) et al.
ANALYSE DIACHRONIQUE, ANALYSE SPATIO-TEMPORELLE, COUVERT FORESTIER,
DEFORESTATION, EPIDEMIE, FORET TROPICALE, IMAGE IRS, MALADIE PARASITAIRE,
NORMALIZED DIFFERENCE VEGETATION INDEX
N° notice
A2012-102
Résumé d'auteur Assam–Arunachal forest fringed foothill area is endemic for malaria incidence. The
present study deals with the temporal analysis of malaria incidence and determines its
association with deforestation in 24 villages along the Assam–Arunachal forest fringed
foothill area of Sonitpur district of Assam. Malaria epidemiological survey has been
carried out in the study area from the year 1994 to 2005. Remote sensing (RS) technique
has been used to map the areas of forest changes from the year 2000 to 2005.
Geographical information system (GIS) was used to map the malaria incidence and forest
cover. The study villages are endemic to malaria infections and there was increasing
trend of malaria incidence over the years. The slide positivity rate (SPR) ranged from
5.1% in 1997 to 44.4% in 2005. The percentage forest cover decreased significantly from
23.6% during 2000 to 15.4% during 2005, whereas SPR was increased during 2000–
2005. The present study is the first attempt to understand the role of deforestation in
malaria incidence using RS and GIS in the north-eastern region of India at a microgeographic level. The study suggests that the area is endemic to malaria transmission.
The decrease in forest cover is a serious ecological concern besides its role in elevating
the malaria incidence in the study area.
Titre
Auteur(s)
Source
Mots clés
An interactive framework for spatial joins: a statistical approach to data analysis in
GIS
ALKOBAISI (S.), BAE (W.), VOJTECHOVSKY (P.) et NARAYANAPPA (S.)
ANALYSE DE DONNEES, ARBRE QUADRATIQUE, ARBRE-R, SYSTEME D'INFORMATION
GEOGRAPHIQUE
N° notice
A2012-090
Résumé d’auteur Many Geographic Information Systems (GIS) handle a large volume of geospatial data.
Spatial joins over two or more geospatial datasets are very common operations in GIS for
data analysis and decision support. However, evaluating spatial joins can be very time
intensive due to the size of datasets. In this paper, we propose an interactive framework
that provides faster approximate answers of spatial joins. The proposed framework
utilizes two statistical methods: probabilistic join and sampling based join. The
probabilistic join method provides speedup of two orders of magnitude with no
correctness guarantee, while the sampling based method provides an order of magnitude
improvement over the full indexing tree joins of datasets and also provides running
_______________________________________________________________________________________
confidence intervals. The framework allows users to trade-off speed versus bounded
accuracy, hence it provides truly interactive data exploration. The two methods are
evaluated empirically with real and synthetic datasets.
Titre
Auteur(s)
Source
Mots clés
A framework for integrating multi-accuracy spatial data in geographical
applications
BELUSSI (A.) et MIGLIORINI (S.)
DONNEES MULTISOURCES, FILTRE DE KALMAN, INFRASTRUCTURE NATIONALE DES
DONNEES LOCALISEES, INTEGRATION DE DONNEES, QUALITE DES DONNEES
N° notice
A2012-109
Résumé d’auteur In recent years the integration of spatial data coming from different sources has become a
crucial issue for many geographical applications, especially in the process of building and
maintaining a Spatial Data Infrastructure (SDI). In such context new methodologies are
necessary in order to acquire and update spatial datasets by collecting new
measurements from different sources. The traditional approach implemented in GIS
systems for updating spatial data does not usually consider the accuracy of these data,
but just replaces the old geometries with the new ones. The application of such approach
in the case of an SDI, where continuous and incremental updates occur, will lead very
soon to an inconsistent spatial dataset with respect to spatial relations and relative
distances among objects. This paper addresses such problem and proposes a framework
for representing multi-accuracy spatial databases, based on a statistical representation of
the objects geometry, together with a method for the incremental and consistent update
of the objects that applies a customized version of the Kalman filter. Moreover, the
framework considers also the spatial relations among objects, since they represent a
particular kind of observation that could be derived from geometries or be observed
independently in the real world. Spatial relations among objects need also to be
compared in spatial data integration and we show that they are necessary in order to
obtain a correct result in merging objects geometries.
Titre
Auteur(s)
Source
Mots clés
Processing aggregated data: the location of clusters in health data
BUCHIN (K.), BUCHIN (M.), VAN KREVELD (M.) et al.
AGREGATION SPATIALE, BASE DE DONNEES SPATIOTEMPORELLES, BASE DE DONNEES
THEMATIQUES, POSITIONNEMENT, REGROUPEMENT DE DONNEES, SANTE
N° notice
A2012-108
Résumé d’auteur Spatially aggregated data is frequently used in geographical applications. Often spatial
data analysis on aggregated data is performed in the same way as on exact data, which
ignores the fact that we do not know the actual locations of the data. We here propose
models and methods to take aggregation into account. For this we focus on the problem
of locating clusters in aggregated data. More specifically, we study the problem of
locating clusters in spatially aggregated health data. The data is given as a subdivision
into regions with two values per region, the number of cases and the size of the
population at risk. We formulate the problem as finding a placement of a cluster window
of a given shape such that a cluster function depending on the population at risk and the
cases is maximized. We propose area-based models to calculate the cases (and the
population at risk) within a cluster window. These models are based on the areas of
intersection of the cluster window with the regions of the subdivision. We show how to
compute a subdivision such that within each cell of the subdivision the areas of
intersection are simple functions. We evaluate experimentally how taking aggregation into
account influences the location of the clusters found.
Titre
Auteur(s)
Source
Mots clés
A fuzzy index for detecting spatiotemporal outliers
GREKOUSIS (G.) et FOTIS (Y.)
DETECTION AUTOMATIQUE, INDEXATION SPATIALE, LOGIQUE FLOUE, VALEUR
ABERRANTE
N° notice
A2012-111
Résumé d’auteur The detection of spatial outliers helps extract important and valuable information from
large spatial datasets. Most of the existing work in outlier detection views the condition of
being an outlier as a binary property. However, for many scenarios, it is more meaningful
to assign a degree of being an outlier to each object. The temporal dimension should also
be taken into consideration. In this paper, we formally introduce a new notion of spatial
_______________________________________________________________________________________
outliers. We discuss the spatiotemporal outlier detection problem, and we design a
methodology to discover these outliers effectively. We introduce a new index called the
fuzzy outlier index, FoI, which expresses the degree to which a spatial object belongs to a
spatiotemporal neighbourhood. The proposed outlier detection method can be applied to
phenomena evolving over time, such as moving objects, pedestrian modelling or credit
card fraud.
Titre
SKIF-P: a point-based indexing and ranking of web documents for spatial-keyword
search
KHODAEI (A.), SHAHABI (C.) et LI (C.)
Auteur(s)
Source
Mots clés
BASE DE DONNEES LOCALISEES, CLASSEMENT, INDEXATION DOCUMENTAIRE
N° notice
A2012-110
Résumé d’auteur There is a significant commercial and research interest in location-based web search
engines. Given a number of search keywords and one or more locations (geographical
points) that a user is interested in, a location-based web search retrieves and ranks the
most textually and spatially relevant web pages. In this type of search, both the spatial
and textual information should be indexed. Currently, no efficient index structure exists
that can handle both the spatial and textual aspects of data simultaneously and
accurately. Existing approaches either index space and text separately or use inefficient
hybrid index structures with poor performance and inaccurate results. Moreover, most of
these approaches cannot accurately rank web-pages based on a combination of space
and text and are not easy to integrate into existing search engines. In this paper, we
propose a new index structure called Spatial-Keyword Inverted File for Points to handle
point-based indexing of web documents in an integrated/efficient manner. To seamlessly
find and rank relevant documents, we develop a new distance measure called spatial tfidf. We propose four variants of spatial-keyword relevance scores and two algorithms to
perform top-k searches. As verified by experiments, our proposed techniques outperform
existing index structures in terms of search performance and accuracy.
Titre
Auteur(s)
Source
Mots clés
PNN query processing on compressed trajectories
SHANG (S.), YUAN (B.) et al.
ITINERAIRE VOISIN LE PLUS PROCHE, RECONSTRUCTION D'OBJET, RESEAU ROUTIER,
TRAJECTOGRAPHIE
N° notice
A2012-107
Résumé d’auteur Trajectory compression is widely used in spatial-temporal databases as it can notably
reduce (i) the computation/communication load of clients (GPS-enabled mobile devices)
and (ii) the storage cost of servers. Compared with original trajectories, compressed
trajectories have clear advantages in data processing, transmitting, storing, etc. In this
paper, we investigate a novel problem of searching the Path Nearest Neighbor based on
Compressed Trajectories (PNN-CT query). This type of query is conducted on
compressed trajectories and the target is to retrieve the PNN with the highest probability
(lossy compression leads to the uncertainty), which can bring significant benefits to users
in many popular applications such as trip planning. To answer the PNN-CT query
effectively and efficiently, a two-phase solution is proposed. First, we use the meta-data
and sample points to specify a tight search range. The key of this phase is that the
number of data objects/trajectory segments to be processed or decompressed should be
kept as small as possible. Our efficiency study reveals that the candidate sets created are
tight. Second, we propose a reconstruction algorithm based on probabilistic models to
account for the uncertainty when decompressing the trajectory segments in the candidate
set. Furthermore, an effective combination strategy is adopted to find the PNN with the
highest probability. The complexity analysis shows that our solution has strong
advantages over existing methods. The efficiency of the proposed PNN-CT query
processing is verified by extensive experiments based on real and synthetic trajectory
data in road networks.
Spatial databases
Titre
Auteur(s)
Mapping the world: GIM international interviews Steve Coast
ANONYME
_______________________________________________________________________________________
Source
Mots clés
N° notice
INFORMATION GEOGRAPHIQUE VOLONTAIRE, OPENSTREETMAP
A2012-051
Steve Coast founded OpenStreetMap in 2004. It's a free, editable map of the world which
has been made by people across the globe and allows users to view, edit and use
geographical data in a collaborative way from anywhere on the planet. GIM International
spoke to him about the project and what lies ahead.
Spatial data infrastructure
Titre
Auteur(s)
Source
Mots clés
The SB-index and the HSB-index: efficient indices for spatial data warehouses
SIQUEIRA (T.), DUTRA DE AGUIAR CIFERRI (C.), TIMES (V.) et al.
ENTREPOT DE DONNEES LOCALISEES, FORMAT BITMAP, INDEX SPATIAL, INDEXATION
SPATIALE, SOLAP
N° notice
A2012-085
Résumé d’auteur Spatial data warehouses (SDWs) allow for spatial analysis together with analytical
multidimensional queries over huge volumes of data. The challenge is to retrieve data
related to ad hoc spatial query windows according to spatial predicates, avoiding the high
cost of joining large tables. Therefore, mechanisms to provide efficient query processing
over SDWs are essential. In this paper, we propose two efficient indices for SDW: the
SB-index and the HSB-index. The proposed indices share the following characteristics.
They enable multidimensional queries with spatial predicate for SDW and also support
predefined spatial hierarchies. Furthermore, they compute the spatial predicate and
transform it into a conventional one, which can be evaluated together with other
conventional predicates by accessing a star-join Bitmap index. While the SB-index has a
sequential data structure, the HSB-index uses a hierarchical data structure to enable
spatial objects clustering and a specialized buffer-pool to decrease the number of disk
accesses. The advantages of the SB-index and the HSB-index over the DBMS resources
for SDW indexing (i.e. star-join computation and materialized views) were investigated
through performance tests, which issued roll-up operations extended with containment
and intersection range queries. The performance results showed that improvements
ranged from 68% up to 99% over both the star-join computation and the materialized
view. Furthermore, the proposed indices proved to be very compact, adding only less
than 1% to the storage requirements. Therefore, both the SB-index and the HSB-index
are excellent choices for SDW indexing. Choosing between the SB-index and the HSBindex mainly depends on the query selectivity of spatial predicates. While low query
selectivity benefits the HSB-index, the SB-index provides better performance for higher
query selectivity.
Titre
Auteur(s)
Source
Mots clés
Reference model for a data grid approach to address data in a dynamic SDI
COETZEE (S.)
DONNEES LOCALISEES NUMERIQUES, OPEN GRID SERVICES ARCHITECTURE, PARTAGE
DE DONNEES LOCALISEES
N° notice
A2012-083
Résumé d’auteur A grid is concerned with the integration, virtualization, and management of services and
resources in a distributed, heterogeneous environment that supports virtual organizations
across traditional administrative and organizational domains. Spatial data infrastructures
(SDI) aim to make spatial data from multiple sources available and usable to as wide an
audience as possible. The first SDIs of the 1990s followed a top–down approach with the
focus on data production and centralization. In recent years, SDIs have seen a huge
increase in the number of participants, necessitating a more dynamic bottom-up
approach. While much research has been done on web services and SDIs, research on
the use of data grids for SDIs is limited. In this paper an emergency response scenario is
presented to illustrate how the data grid approach can be used as a decentralized
platform for address data in a dynamic SDI. Next, Compartimos (Spanish for ‘we share’)
is presented, a reference model for an address data grid in an SDI based on the Open
Grid Services Architecture (OGSA). Compartimos identifies the essential components
and their capabilities required for a decentralized address data grid in a dynamic SDI. It
deviates from the current centralized approach, allows data resources to come and go
_______________________________________________________________________________________
and node hosts to grow and shrink as necessary. An address data grid in an SDI is both
a novel application for data grids as well as a novel technology in SDI environments and
thus advances the mutual understanding between data grids and SDIs. In conclusion,
additional research required for address data grids in SDIs is discussed.
Titre
Auteur(s)
Source
Mots clés
N° notice
Surveying the changing face of Britain
BEAVIS (B.)
Titre
Auteur(s)
Source
Mots clés
Towards a common understanding in cartographic design
HOPSTOCK (A.)
GEOMETRE, LEVER TOPOGRAPHIQUE, METIER, MISE A JOUR DE BASE DE DONNEES
A2012-039
As Britain's national mapping agency, Ordnance Survey's role is to collect, maintain and
distribute the most accurate and up-to-date geographic information (GI) of the nation...A
resource on which government, businesses and individuals rely. Bob Beavis explains
how its field surveyors go about their task.
CONCEPTION CARTOGRAPHIQUE, INFRASTRUCTURE EUROPEENNE DES DONNEES
LOCALISEES, INSPIRE, SPECIFICATION DE PRODUIT
N° notice
A2012-040
Résumé d’éditeur Harmonisation of cartographic design - as well as feature and attribute concepts - is
essential in the context of a pan-European spatial data infrastructure. So argues Dr Anja
Hopfstock of Germany's federal agency for cartography and geodesy (BKG) in this oneto-one with Esri staff writer, Karon Richardon.
Webgeomatics
Titre
Auteur(s)
Source
Mots clés
WebGIS performance tests
DAI (H.), CHEN (L.) et CHEN (C.)
ANALYSE COMPARATIVE, ARCHITECTURE A TROIS NIVEAUX, DIFFUSION DE DONNEES,
SERVEUR D'APPLICATION, TEST DE PERFORMANCE, TRAITEMENT REPARTI, WEBSIG
N° notice
A2012-006
Résumé d’auteur A webGIS is usually constructed as a multi-tiers architecture basically consisting for the
client side, the server side and the database component. From the client side, users send
queries or requests to the server via (wireless) internet. Next the server communicates
with database, where the requested information is compiled by the database server.
Finally, the result is sent to the client. With the rapid growth of WebGIS application in
2010, the authors tested the performance of two models: centralized and distributed.
Titre
Auteur(s)
Source
Mots clés
Integrating GI with non-GI services — showcasing interoperability in a
heterogeneous service-oriented architecture
TREMBLMAYR (M.), SCHEIDER (S.), KRUGER (A.) et al.
ARCHITECTURE ORIENTEE SERVICE, HETEROGENEITE SEMANTIQUE,
INTEROPERABILITE, LOGICIEL DE GESTION INTEGREE, ONTOLOGIE, SERVICE WEB,
SERVICE WEB GEOGRAPHIQUE
N° notice
A2012-086
Résumé d’auteur The concept of a service-oriented architecture provides a technical foundation for
delivering, using, and integrating software. It can serve as an approach to integrate GIS
with other, non-GIS applications. This paper presents and discusses a service-oriented
architecture that embraces a GIS and an enterprise resource planning system. The two
information systems make mutually required functionalities available as services. This
defines the showcase for making GI and non-GI services syntactically and semantically
interoperable. The services-based integration leverages open-standard interfacing and,
thus, removes syntactic heterogeneity. The integration is discussed in terms of an
emergency management scenario. This scenario also helps to outline challenging
semantic interoperability issues. When services provided by GIS and non-GIS
applications interact, the problem arises how their different conceptualizations should be
mapped. This paper analyzes essential ontological distinctions for mapping conceptual
_______________________________________________________________________________________
schemes in GI locator services and non-GI services. It proposes a hybrid decentralized
approach of concept mapping, based on a common top-level ontology.
Titre
Auteur(s)
Source
Mots clés
An evaluation of ontology matching in geo-service applications
VACCARI (L.), SHVAIKO (P.), PANE (J.) et al.
APPARIEMENT SEMANTIQUE, HETEROGENEITE SEMANTIQUE, INTEROPERABILITE
SEMANTIQUE, ONTOLOGIE, SERVICE WEB GEOGRAPHIQUE, SIMILITUDE SEMANTIQUE,
WEB SEMANTIQUE
N° notice
A2012-081
Résumé d’auteur Matching between concepts describing the meaning of services representing
heterogeneous information sources is a key operation in many application domains,
including web service coordination, data integration, peer-to-peer information sharing,
query answering, and so on. In this paper we present an evaluation of an ontology
matching approach, specifically of structure-preserving semantic matching (SPSM)
solution. In particular, we discuss the SPSM approach used to reduce the semantic
heterogeneity problem among geo web services and we evaluate the SPSM solution on
real world GIS ESRI ArcWeb services. The first experiment included matching of original
web service method signatures to synthetically alterated ones. In the second experiment
we compared a manual classification of our dataset to the automatic (unsupervised)
classification produced by SPSM. The evaluation results demonstrate robustness and
good performance of the SPSM approach on a large (ca. 700 000) number of matching
tasks.
Titre
Auteur(s)
Source
Mots clés
Automatic geospatial metadata generation for earth science virtual data products
YUE (P.), GONG (J.), DI (L.) et al.
DONNEES LOCALISEES NUMERIQUES, FLUX DE TRAVAUX, METADONNEES, PRODUIT
GEOGRAPHIQUE VIRTUEL, SERVICE WEB GEOGRAPHIQUE, WEB SEMANTIQUE
N° notice
A2012-080
Résumé d’auteur Recent advances in Semantic Web and Web Service technologies has shown promise for
automatically deriving geospatial information and knowledge from Earth science data
distributed over the Web. In a service-oriented environment, the data, information, and
knowledge are often consumed or produced by complex, distributed geoscientific
workflows or service chains. In order for the chaining results to be consumable, sufficient
metadata for data products to be delivered by service chains must be provided. This
paper proposes automatic generation of geospatial metadata for Earth science virtual
data products. A virtual data product is represented using process models, and can be
materialized on demand by dynamically binding and chaining archived data and services,
as opposed to requiring that Earth science data products be physically archived.
Semantics-enabled geospatial metadata is generated, validated, and propagated during
the materialization of a virtual data product. The generated metadata not only provides a
context in which end-users can interpret data products before intensive execution of
service chains, but also assures semantic consistency of the service chains.
Titre
Auteur(s)
Source
Mots clés
A sensor web for Europe
KJELD (P.), JIRKA (S.) et BRORING (A.)
DONNEES ENVIRONNEMENTALES, EXPLOITATION DE CAPTEURS WEB, PARTAGE DE
DONNEES LOCALISEES
N° notice
A2012-113
Résumé d’éditeur Peter Kjeld, Simon Jirka and Arne Bröring relate how sensor web enablement will
transform Europe’s ability to share environmental data across organizational, political and
national Boundaries.
Titre
Auteur(s)
Source
Mots clés
N° notice
Résumé d’auteur
Blind and squaring-resistant watermarking of vectorial building layers
LAFAYE (J.), BEGUEC (J.), GROSS (D.) et RUAS (A.)
BASE DE DONNEES LOCALISEES, BATI, DROIT D'AUTEUR, TATOUAGE NUMERIQUE
A2012-088
Due to the ease of digital copy, watermarking is crucial to protect the intellectual property
of rights owners. We propose an effective watermarking method for vectorial
geographical databases, with the focus on the buildings layer. Embedded watermarks
_______________________________________________________________________________________
survive common geographical filters, including the essential squaring and simplification
transformations, as well as deliberate removal attempts, e.g. by noise addition, cropping
or over-watermarking. Robustness against the squaring transformation is not addressed
by existing approaches. The impact on the quality of the data sets, defined as a
composition of point accuracy and angular quality, is assessed through an extensive
series of experiments. Our method is based on a quantization of the distance between
the centroid of the building and its extremal vertex according to its orientation.
Titre
Auteur(s)
Source
Mots clés
Towards dynamic behavior-based profiling for reducing spatial information
overload in map browsing activity
MAC AOIDH (E.), BERTOLOTTO (M.) et WILSON (D.)
COMPORTEMENT, DONNEES LOCALISEES, FILTRAGE, INTERFACE UTILISATEUR,
SUPERPOSITION DE DONNEES, SYSTEME D'INFORMATION GEOGRAPHIQUE,
VISUALISATION DE DONNEES
N° notice
A2012-105
Résumé d’auteur The quantity of available detailed spatial content over the Web is continually growing.
This leads to the problems of information overload and lengthy map download and render
times. In order to address these problems in an effective and unobtrusive manner, the
available content must be implicitly filtered and prioritized according to the user’s
interests. Personalization of the user’s map elides less relevant information and prioritizes
relevant information. The authors previously introduced a novel technique for detailed
behavior-based spatial profiling. This article provides an analysis of the technique while
exploring the properties of user interactions with a typical Web-based map browsing
system. A technique for the automatic identification of specific interaction patterns is
introduced and explored in a bid to improve current behavior-based map personalization
techniques. The goal of this work is to move towards real-time profiling to support spatial
dataset personalization, thus improving the user experience by reducing information
overload.
Titre
Auteur(s)
Source
Mots clés
Retrospective adaptive prefetching for interactive Web GIS applications
YESILMURAT (S.) et ISLER (V.)
ALGORITHME D'UTILISATION DE L'ANTEMEMOIRE, MISE A JOUR AUTOMATIQUE,
TELECHARGEMENT, TRAITEMENT INTERACTIF, WEBSIG
N° notice
A2012-106
Résumé d’auteur A major task of a Web GIS (Geographic Information Systems) system is to transfer map
data to client applications over the Internet, which may be too costly. To improve this
inefficient process, various solutions are available. Caching the responses of the requests
on the client side is the most commonly implemented solution. However, this method may
not be adequate by itself. Besides caching the responses, predicting the next possible
requests from a client and updating the cache with responses for those requests together
provide a remarkable performance improvement. This procedure is called “prefetching”
and makes caching mechanisms more effective and efficient. This paper proposes an
efficient prefetching algorithm called Retrospective Adaptive Prefetch (RAP), which is
constructed over a heuristic method that considers the former actions of a given user.
The algorithm reduces the user-perceived response time and improves user navigation
efficiency. Additionally, it adjusts the cache size automatically, based on the memory size
of the client’s machine. RAP is compared with four other prefetching algorithms. The
experiments show that RAP provides better performance enhancements than the other
methods.
_______________________________________________________________________________________

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