Etablissement d'un modèle numérique de terrain sur une zone sismique active d'Arménie

Falala L.. 1997. Etablissement d'un modèle numérique de terrain sur une zone sismique active d'Arménie. Marne-la-Vallée : ENSG, 55 p. Mémoire d'ingénieur : Ecole nationale des sciences géographiques

Autre titre : Computing a digital elevation model among a sismic area in Armenia

Résumé : The aim of this project is to compute a digital elevation model (DEM) along a fault in Armenia. Two methods: automatic correlation of satellite images and extraction of altimetric information from topographical maps were tested and compared. GEOIMAGE software was used to generate a DEM from a panchromatic SPOT images stereopair. Automatic correlation algorithm, based on a multi-resolution approach, researches homologuous countourlines in the two images. With few land-marks, satellite's orbit data can be precised. It makes the algorith more efficient but many mistakes remain. They have to be corrected manually, which is very long in spite of interactive tools. The second method is the extraction of altimetric information from topographical maps. At first, most of contour lines had to be redrawn on tracing paper which is scanned. Then classification, binarization and vectorisation of the image transform raster information in objects with attributes. Labbeling the contour lines is the last step before DEM interpolation. A GEOIMAGE module was built to do semi-automatic extraction of contour lines but the results in Armenia were too bad so that I used ARC/INFO which gives better results. The DEM Was calculated with a triangular irregular network (TIN). A fine adjustment of tolerances is very important to get high quality DEM. Comparaison of the two DEM shows that some correlation mistakes ramain in the SPOT DEM and that gorges can not be detected by automatic correlation.

Mots-clés Agrovoc : modèle, cartographie, télédétection

Mots-clés géographiques Agrovoc : Arménie

Classification Agris : U30 - Méthodes de recherche

Auteurs et affiliations

• Falala L.

Source : Cirad - Agritrop (https://agritrop.cirad.fr/309118/)

Métriques

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