Format of Terrain Map File

The terrain maps are stored in the surface_height.conf file in the ${IRIS_CONFIG} directory.

This file contains information for each radar site stored in an ASCII polar format. Here are the first few lines of such a file:

SITE Boston
AZ_RESOLUTION 1.0
RANGE_RESOLUTION 1.0 300.0
AZ 0
5
3
3
3
8
14
15
12
10

  1. The SITE command indicates the site name for data until the next SITE command.

  2. The AZ_RESOLUTION specifies the azimuth resolution of the file. In this case it is 1°.

    We expect to find 360 different azimuths in the file. Match this to your normal azimuth resolution, though it finds the closest in any case.

  3. The RANGE_RESOLUTION specifies the range step in km, and the total number of km we are going to.
  4. In this case, 1 km (0.6 mi) steps out to 300 km (186.4 mi).

  5. Next is the AZ command, followed by the surface altitude in meters for each km in range.

  6. After 300 altitudes there is another AZ command and then possibly another SITE command.