Calculer la surface sous le niveau de la mer

BrunoDI_GIUSTO

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Bonjour à tous. <\/SPAN><\/P>Quelle serait la meilleure méthode pour calculer, à partir d'un DEM et d'un shapefile avec les polygones des communes, la surface totale de chaque commune qui est sous le niveau de la mer, s'il vous plaît ? <\/SPAN><\/P>Merci d'avance pour votre aide !<\/SPAN><\/P><\/BODY><\/HTML>

BrunoDI_GIUSTO

1- raster calculator (in Spatial Analyst Tools/Map Algebra) with [original DEM] <= 0 which produce a new raster with two categories, one above sea level and another below sea level

2- Tabulate area (in Spatial Analyst Tools/Surface/Zonal/) which calculate the surface of each previous categories within the polygons of the shapefile.

3- in the table created, create a new field for the total surface of the two categories.

4- in the same table, create a new field for the percentage of submerged land with surface of submerged land / total surface. Click on properties on the percent field, then click percentage, then Numeric, then all frequencies are percentage, adjust the number of decimals.

5-Spatial join the table to the original table of the shapefiles of the communes. End