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Titre : SIG disponibilités alimentaires dans la ville de Ouagadougou Type de document : Mémoire Auteurs : Benoit Antoine, Auteur Editeur : Champs-sur-Marne : Ecole nationale des sciences géographiques ENSG Année de publication : 2007 Importance : 67 p. Format : 21 x 30 cm Note générale : Rapport de projet pluridisciplinaire, cycle des ingénieurs diplômés de l'ENSG 2ème année (IT2) Langues : Français (fre) Descripteur : [Vedettes matières IGN] Systèmes d'information géographique
[Termes IGN] acquisition de données
[Termes IGN] analyse spatiale
[Termes IGN] ArcGIS
[Termes IGN] données GPS
[Termes IGN] enquête
[Termes IGN] milieu urbain
[Termes IGN] Ouagadougou
[Termes IGN] sécurité alimentaire
[Termes IGN] système d'information géographiqueIndex. décimale : PROJET Mémoires : Rapports de projet - stage des ingénieurs de 2e année Résumé : (Auteur) Ce stage de 12 semaines avait pour but la réalisation d'un SIG portant sur la répartition et les facteurs de la vulnérabilité alimentaire dans la ville de Ouagadougou, capitale du Burkina Faso. Ce stage, effectué au sein de l'Institut de Recherche pour le Développement, s'est déroulé en deux partie distinctes : la réalisation d'une enquête de terrain de deux mois, avec le concours de 6 étudiants, et la conception même du SIG. L'enquête a été effectuée sur un ensemble de 60 zones de dénombrement dans lesquelles tous les lieux de vente d'alimentation, les zones cultivées, les élevages d'animaux et les points d'eau ont été référencés. Le SIG a ensuite permis une première analyse des conditions d'accès à l'alimentation de la population de Ouagadougou. Par cette étude, j'ai voulu poser ma pierre sur le grand chantier de la lutte contre la malnutrition dans les pays d'Afrique subsaharienne. Note de contenu : Utilité d'un SIC pour la ville de Ouagadougou
Le Burkina Faso
La vulnérabilité alimentaire à Ouagadougou
Insertion du sujet de stage dans les projets de recherche en cours
Récolte des données
Préparation de l'enquête
Management de la récolte des données
Principales difficultés de terrain
Réalisation du SIC
Outils disponibles
Méthodes
Résultats
Discussion et interprétationNuméro de notice : 19135 Affiliation des auteurs : IGN (1940-2011) Thématique : GEOMATIQUE/INFORMATIQUE Nature : Mémoire de projet pluridisciplinaire Organisme de stage : Institut de Recherche pour le Développement IRD Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=51074 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 19135-01 PROJET Livre Centre de documentation Travaux d'élèves Disponible 19135-02 PROJET Livre Centre de documentation Travaux d'élèves Disponible Spatial data access by the Grassroots / Renee E. Sieber in Cartography and Geographic Information Science, vol 34 n° 1 (January 2007)
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[article]
Titre : Spatial data access by the Grassroots Type de document : Article/Communication Auteurs : Renee E. Sieber, Auteur Année de publication : 2007 Article en page(s) : pp 47 - 62 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes d'information géographique
[Termes IGN] accès aux données localisées
[Termes IGN] analyse spatiale
[Termes IGN] approche participative
[Termes IGN] base de données localisées
[Termes IGN] données localisées
[Termes IGN] infrastructure nationale des données localisées
[Termes IGN] interopérabilité
[Termes IGN] organisation non gouvernementale
[Termes IGN] organisme sans but lucratif
[Termes IGN] participation du public
[Termes IGN] SIG participatifRésumé : (Auteur) This paper characterizes efforts by nonprofit organizations to access spatial data developed by government agencies. It is based on research conducted in California, a U.S. state that is positioned at the forefront of nonprofit usage of GIS. The research, conducted over a ten-year period, followed six best practices case studies of small conservation and environmental organizations using GIS. Case study research is analyzed in a framework developed from the literature on public participation GIS and inter-organizational GIS. The research revealed that access was structured by technical details, such as adjusting agencies' thematic categories, fluctuations in foundation funding and other organizational/political issues, and inter-organizational linkages in the emergent spatial data intermediary sector. Overall, access was conditioned by the legal and economic regimes in which the cases conducted their advocacy. Ultimately, access to data profoundly shaped GIS applications and nonprofit activities, occasionally shifting or even precluding activism, provoking creative mechanisms to obtain data, or inducing innovative usage of available data. Copyright CaGISociety Numéro de notice : A2007-103 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE/INFORMATIQUE Nature : Article DOI : 10.1559/152304007780279087 En ligne : https://doi.org/10.1559/152304007780279087 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28468
in Cartography and Geographic Information Science > vol 34 n° 1 (January 2007) . - pp 47 - 62[article]Réservation
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Titre : Towards a rigorous logic for spatial data representation Type de document : Thèse/HDR Auteurs : Rodney James Thompson, Auteur Editeur : Delft : Netherlands Geodetic Commission NGC Année de publication : 2007 Collection : Netherlands Geodetic Commission Publications on Geodesy, ISSN 0165-1706 num. 65 Importance : 332 p. Format : 17 x 24 cm ISBN/ISSN/EAN : 978-90-6132-303-7 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes d'information géographique
[Termes IGN] données localisées
[Termes IGN] données vectorielles
[Termes IGN] logique
[Termes IGN] modèle conceptuel de données localisées
[Termes IGN] primitive géométrique
[Termes IGN] représentation des données
[Termes IGN] traitement automatique de donnéesRésumé : (Auteur) The storage and retrieval of spatial data in computer systems has matured greatly over recent years, from the earliest approaches (of simple digitised linework and text) to the representation of features and their attributes, with the semantics of their behaviour associated. This has led to massive cost savings where data, which might have been captured for a specific purpose, can be shared and reused for other purposes.
In this first generation of Geographic Information Systems (GIS), the data is stored locally, with each vendor using different nomenclature and definitions of spatial objects and having very different rules for what is accepted as ''valid''. As a result a scientist using a desktop GIS may need to expend a considerable portion of his/her research effort and funds in translating, cleaning and preparing pre-existing data to convert to the form required for the study.
For some years now, there has been a trend towards spatial data being housed within a database management system, these being considered as a corporate resource, leading to the realisation that the geographic data itself is in fact an infrastructure, in the same way as is, for example, a telephone network. This moves the ownership of the data from the desktop, firstly to the corporation, and ultimately to being a shared resource between public and private organisations - a Geographic Information Infrastructure (GII).
An inhibiting factor in these trends is the lack of standardisation alluded to above. Where every data sharing operation involves manual intervention, it is difficult, if not impossible to create a GII. Thus a strong and consistent set of standards is needed, with the most basic requirement being for consistency in the geometric concepts used. While progress is being made by groups such as the International Standards Organisation Technical Committee 211 (ISO TC211) and the Open Geospatial Consortium (OGC), there is still much to be done.
The success of these standardisation efforts has been compromised by the requirement to be vendor neutral - i.e. to avoid specifying an internal representation to be used for storage. For example, the standards will remain silent on whether coordinate values should be stored in floating point or integer format.
As a result, definitions of spatial objects are expressed in mathematical terms assuming an infinite precision real number system, with the details of how this is to be translated into the computational representation being left to the implementer. Therefore there is no agreed normative meaning of the ''equals'' predicate when applied to geometric objects, and definitions of validity are in general left to the implementers.
If the standardisation effort is to allow spatial data to be interchanged without expensive manual intervention, a well defined logic is needed to underpin the standards and support the definition of validity of that data. This would also ensure that inferences drawn from the digital model remain consistent and do not lead to logical fallacies.
The language of spatial databases is couched in the language of mathematics, with operations being given names such as ''union'' and ''intersection'' and using vector-like representations. This naturally leads to the impression that the representations form a topological and/or vector space. Unfortunately this is not the case. Generally speaking, the rigorous mathematics used in the definition of spatial objects ends outside the database representation, which is only an approximation of the theoretical formalism used to define it.
This thesis documents a number of cases that illustrate the potential breakdown of logic to be found in current technology, for example, cases where the union or intersection operations lead to inconsistent results. Various alternative approaches that have been investigated in search of solutions are discussed, and their advantages and disadvantages indicated.
This current research has been motivated by an attempt to apply the mathematical approach to the actual representation of spatial features within the computer system. In this rigorous approach, the assumptions (or ''axioms'') are clearly identified, and used to develop a chain of argument, leading to a proof of the required proposition. The advantage of this approach in the field of spatial data representation is that, if the computer hardware can be verified to obey the axioms, then the correct results of the algorithms are assured.
In order to facilitate such a chain of proof, a form of representation known as the regular polytope has been defined, based on a small set of axioms and definitions, and shown to possess a consistent and complete logic. That is to say, the computational representation itself expresses the algebraic formalism, rather than being an approximation to an idealized mathematical model.
Thus this representation is capable of providing a potential storage structure for a useful class of features, but this should not be seen as the sole object of the research. Rather the regular polytope should be seen as an exemplar for any approach to spatial data representation and storage.
The fact that this particular representation can be axiomatically defined and implemented demonstrates that such an approach is feasible, and opens the possibility that all computational representations can be similarly analysed. The regular polytope is a particularly tractable construct for this type of analysis, which is the reason for choosing it. By contrast the kind of structure embedded in many current systems is far more complex. In particular, floating point numbers add a significant level of complexity, and only the most basic topological behaviour has been proved where floating point operations are assumed.
Based on integer and domain restricted rational arithmetic, it is shown that the logic of topology, the Boolean connection algebra and the region connection calculus can be expressed directly by the database implementation. Thus a database built on this structure cannot suffer from the kinds of breakdown of logic discussed above. In addition, this raises the prospect of a definition of validity and robustness of representation that is not vendor specific.
A regular polytope representation of spatial objects is defined as the union of a finite set of (possibly overlapping) "convex regular polytopes", which are in turn defined as the intersection of a finite set of half spaces. These half spaces are defined by finite precision number representations. The term ''Regular Polytope'' here does not carry its conventional meaning as the generalisation of a regular polyhedron (one having equal sides, faces and angles etc.). In the form used here, it combines the topological term ''regular'' with the conventional geometric meaning of ''polyhedron''.
The actual definition is given in axiomatic form, structured so as to form a ''boundary free'' representation, valid in any number of dimensions. Although it is explored here principally in 3D, particular reference is made to the mixture of 2D and 3D found in many current application areas such as cadastral property boundaries. Particular attention is paid to the issue of connectivity, both within and between regular polytopes, and the resultant logic is developed in terms of well studied concepts such as the region connection calculus.
The particular representation chosen for the half space is such that adjoining regular polytopes will have no points in common, and no points will exist between them. Thus it is possible to define a complete partition of space where every point that can be represented computationally is defined to exist in one and only one region. In the traditional representations of 2D polygons and 3D polyhedrons, points play a very important role of carrying the metric information. This is in contrast to regular polytopes where points do not play a role in the definition at all. Instead the metric is specified via the half planes using 3 or 4 integers (in 2D and 3D respectively).
This theoretic basis is then applied to actual database schema design, and several alternative models proposed and analysed. As a check on the practicality of the algorithms, ''proof of concept'' classes have been developed in the Java programming language, and tested on a significant set of cadastral parcels (2D and 3D) from the Queensland cadastre.
Finally, further areas of research are identified, including extensions of the approach to wider problem domains.Note de contenu : 1. Introduction
1.1. Research Question
1.2. Research Approach
1.3. Scope of Research
1.4. Nomenclature
1.5. Computational Representation of Vector Spatial Data
1.6. Contribution of this Work
1.7. Organisation of the Thesis
2. Case Studies
2.1. Case 1. Polygon Union
2.2. Case 2. Data Interchange
2.3. Case 3. ISO 19107 Definition of Equality
2.4. Case 4. ISO 19107 Definition of Simplicity
2.5. Case 5. Intersection of a Point with a Line
2.6. Case 6. Narrow Cadastral Parcels
2.7. Case 7. 3D Surfaces and Lines
2.8. Case 8. ISO 19107 Definition of "interior to" association
2.9. Case 9. Adjoining polygon points
3. Related Work and Theory
3.1. Historic Perspective
3.2. Spatial Logic
3.3. Precision of Calculations and Representation
3.4. The Digital Representation
3.5. Conclusions
4. The Regular Polytope Representation
4.1. The Regular Polytope
4.2. Properties of the Regular Polytope Representation
4.3. Integer Approach
4.4. Domain-Restricted Rational Number Approach
4.5. Floating Point Number Approach
4.6. Conclusion
5. Connectivity in the Regular Polytope Representation
5.1. Connectivity of Geometric Objects
5.2. Connectivity of Convex Polytopes
5.3. Connectivity of Regular Polytopes
5.4. Properties of CA and CB
5.5. Further Connectivity Relations
5.6. Partitioning of Space
5.7. Robustness of Regular Polytopes
5.8. Robustness of Connected Regular Polytopes
5.9. Conclusions
6. Algebras of Connectivity
6.1. The Region Connection Calculus (RCC)
6.2. The Spatial Relations on Regular Polytopes
6.3. Dimensionality of Overlap
6.4. Proximity Space
6.5. Boolean Connection Algebra
6.6. Properties of the Space of Regular Polytopes
6.7. The Convex Hull
6.8. Expressiveness of the Relations and Functions
6.9. Relationship with Constraint Databases
6.10. Conclusions
7. The Data Model
7.1. Vertex-based Representations
7.2 The Discrete Regular Polytope Model
7.3. Topological Encoding of Regular Polytopes
7.4. The Approximated Polytope Model
7.5. Extension to Topological Encoding
7.6. Spatial Indexing of the Regular Polytope
7.7. Relationship with Other Approaches
7.8. Summary of Data Volumes
7.9. Conclusions
8. Implementation Issues
8.1. Rationale for the Approach Taken
8.2. Description of the Java Objects
8.3. Proof of Concept Data
8.4. Algorithmic Complexity
8.5. Optimising the Model
8.6. Data Load Issues
8.7. Conclusions
9. Review of Case Studies
9.1. Case 1. Polygon Union
9.2. Case 2. Data Interchange
9.3. Case 3. ISO 19107 Definition of equalsQ
9.4. Case 4. ISO 19107 Definition of isSimpleQ
9.5. Case 5. Intersection of a Point with a Line
9.6. Case 6. Narrow Cadastral Parcels
9.7. Case 7. 3D Surfaces and Lines
9.8. Case 8. ISO 19107 Definition of "interior to" Association
9.9. Case 9. Adjoining Polygon Points
9.10. Case 10. 3D Cadastre Issues
9.11. Case 11. Datum Conversion
9.12. Case 12. Uniqueness Of Representation
9.13. Case 13. GeoTools/GeoAPI definition of Object.equalsQ
9.14. Conclusions
10. Conclusions
10.1. Application of the Regular Polytope to Lower Dimensionality
10.2. Learnings and Future Research
10.3. ConclusionNuméro de notice : 15360 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE/INFORMATIQUE Nature : Thèse étrangère DOI : sans En ligne : https://www.ncgeo.nl/downloads/65Thompson.pdf Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=62702 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 15360-01 37.30 Livre Centre de documentation Géomatique Disponible n° 82 - décembre 2006 (Bulletin de SIG la lettre)
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Titre : n° 82 - décembre 2006 Type de document : Périodique Année de publication : 2006 Importance : 16 p. Langues : Français (fre) Descripteur : [Vedettes matières IGN] Systèmes d'information géographique Numéro de notice : 286-0610 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE/INFORMATIQUE Nature : Numéro de périodique Permalink : https://documentation.ensg.eu/index.php?lvl=bulletin_display&id=11681 [n° ou bulletin] Contient
- INSPIRE, c'est parti ! / Françoise de Blomac in SIG la lettre, n° 82 (décembre 2006)
- Peut-on mesurer les effets du CRIGE PACA ? / Françoise de Blomac in SIG la lettre, n° 82 (décembre 2006)
- La grande brouille ? / Françoise de Blomac in SIG la lettre, n° 82 (décembre 2006)
- La panoplie SPOT image / Françoise de Blomac in SIG la lettre, n° 82 (décembre 2006)
- La grande illusion de la précision / Françoise de Blomac in SIG la lettre, n° 82 (décembre 2006)
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Code-barres Cote Support Localisation Section Disponibilité 286-06101 RAB Revue Centre de documentation En réserve L003 Disponible An examination of GIS success within local government departments in the U.K. and in Trinidad and Tobago / S.M. Baban in Surveying and land information science, vol 66 n° 4 (01/12/2006)
[article]
Titre : An examination of GIS success within local government departments in the U.K. and in Trinidad and Tobago Type de document : Article/Communication Auteurs : S.M. Baban, Auteur ; B. Ramlal, Auteur Année de publication : 2006 Article en page(s) : pp 269 - 277 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes d'information géographique
[Termes IGN] analyse comparative
[Termes IGN] Angleterre
[Termes IGN] collectivité territoriale
[Termes IGN] évaluation des données
[Termes IGN] infrastructure nationale des données localisées
[Termes IGN] Pays de Galles
[Termes IGN] système d'information géographique
[Termes IGN] Trinité-et-TobagoRésumé : (Auteur) The levels of GIS use in local government departments in the U.K and in Government Departments in Trinidad and Tobago are examined. A representative sample of 22 local government departments in England and Wales and 10 government departments in Trinidad was used. The “success” in the level of GIS use as well as implementation approaches was evaluated based on two sets of five indicators derived from the literature. The indicators were used as benchmarks against which the performance of the departments was assessed and ranked. The results indicate that GIS use and implementation levels vary. These variations showed a significant relationship to the approach adopted by each of the authorities in introducing and implementing GIS. The outcomes also indicate that GIS implementation and usage in Trinidad and Tobago are similar to those in the U.K. but with a time lag of about five years. Copyright SaLIS Numéro de notice : A2006-607 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE/INFORMATIQUE Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28330
in Surveying and land information science > vol 66 n° 4 (01/12/2006) . - pp 269 - 277[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 121-06041 RAB Revue Centre de documentation En réserve L003 Disponible Permalinkn° 81 - novembre 2006 (Bulletin de SIG la lettre)
Permalinkn° 80 - octobre 2006 (Bulletin de SIG la lettre)
PermalinkGIS: the need to print / A. Kannekens in GEO: Geoconnexion international, vol 5 n° 10 (november - december2006)
PermalinkPermalinkSIHREN : conception de systèmes d'information spatio-temporelle dédiés aux risques naturels / Paule-Annick Davoine in Revue internationale de géomatique, vol 16 n°3 - 4 (septembre – novembre 2006)
PermalinkUn système géomatique de préparation aux interventions d'urgence dans le bassin du Mékong : modèle conceptuel de données pour la sécurité et la santé publique lors d'inondations / G. Aube in Revue internationale de géomatique, vol 16 n°3 - 4 (septembre – novembre 2006)
Permalinkn° 79 - septembre 2006 (Bulletin de SIG la lettre)
PermalinkOpenCIS: open source GIS-based web community information system / D. Caldeweyher in International journal of geographical information science IJGIS, vol 20 n° 8 (september 2006)
PermalinkCreating a hydrographic network from its cartographic representation: a case study using Ordnance Survey mastermap data / Nicolas Regnauld in International journal of geographical information science IJGIS, vol 20 n° 6 (july 2006)
Permalinkn° 78 - juin 2006 (Bulletin de SIG la lettre)
PermalinkGeowind : un savoir-faire, un logiciel / P. Alexandre in Le monde des cartes, n° 188 (juin - août 2006)
PermalinkHandling high-level queries in location-based services for user groups / P. Partsinevelos in Geoinformatica, vol 10 n° 2 (June - August 2006)
PermalinkOpen source software enters GIS market: UMN mapserver and GVSIG most potential ones / A.A. Alfaro in Geoinformatics, vol 9 n° 4 (01/06/2006)
PermalinkVers une intégration des SIG participatifs aux processus de design urbain délibératifs / D.L. Ciobanu in Revue internationale de géomatique, vol 16 n° 2 (juin – août 2006)
Permalinkn° 77 - mai 2006 (Bulletin de SIG la lettre)
PermalinkA multiangular object-oriented framework supporting spatio-temporal granularity conversions / Elena Camossi in International journal of geographical information science IJGIS, vol 20 n° 5 (may 2006)
PermalinkPrincipes et mise en œuvre de PostGIS (2e partie) / D. Faivre in Géomatique expert, n° 50 (01/05/2006)
Permalinkn° 76 - avril 2006 (Bulletin de SIG la lettre)
PermalinkAn evolutionary algorithm for multicriteria path optimization problems / P. Mooney in International journal of geographical information science IJGIS, vol 20 n° 4 (april 2006)
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