How do I create a custom evaluation of Digital Elevation Model (DEM)?

Home > Frequently Asked Questions > How do I create a custom evaluation of Digital Elevation Model (DEM)?

To avoid problems of negative values in GeoTiff format, we have integrated DEM in a way that:

  • elevation above the sea level is stored as it is (e.g. 0-8.848 meters)
  • elevation bellow sea level is stored from 65535 downward (e.g. "-10 meters" is stored as 65525)

To implement your own visualization, you can write a script along the following ways, e.g. "terrain if sea level rises for 2 meters":

if (DEM >= 32768) {
  elevation = DEM - 65535.0;
} else {
  elevation = DEM;
}

if (elevation > 2.0) {
  return [0,0,1];
} else {
  return [elevation/1000,elevation/1000,elevation/1000];
}