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