Digital Elevation Tools

c2cgeoportal applications include web services for getting DEM information. The raster web service allows getting information for points. The profile web service allows getting information for lines.

To configure these web services, you need to set the raster variable in the application config (vars_<project>.yaml). For example:

    cache_size: 21
        file: /var/sig/altimetrie/mns.vrt
        type: gdal
        round: 1
        file: /var/sig/altimetrie/mnt.vrt
        type: gdal
        round: 1

raster is a list of “DEM layers”. There are only two entries in this example, but there could be more.

cache_size is the number of DEM files to keep in cache. Default is 10.

file provides the path to the shape index that references the raster files. The raster files should be in the Binary Terrain (BT/VTP .bt 1.3) format. One may use GDAL/OGR to convert data to such a format.

type shp_index (default) for Mapserver shape index, or gdal for all supported GDAL sources. We recommend to use a vrt file built with gdalbuildvrt.

round specifies how the result values should be rounded. For instance ‘1’: round to the unit, ‘0.01’: round to the hundredth, etc.

nodata specifies the nodata value. By default the nodata value is directly read from the source.

The application viewer should be configured with one (or more) of the ContextualData and the Profile CGXP plugins for the DEM data to be viewable in the web application.