ogxp_update_dsf_Zvert.py

DESCRIPTION

Updates vertex Z in text DSF files based on shapefile polygon boundaries and accompanying control point files.

Burns areas of constant elevation based on elevation data field in shapefile.

For areas of varying elevation, creates spline or ramp surface (depending on number of control points) in GeoTIFF format based on boundary polygon shapefile and accompanying control point file (comma-delimited longitude,latitude,z in meters). Areas outside of boundary polygon are set to null.

The minimum number of control points for creating a spline surface is 9. Two controls points will yield a ramp surface based on the slope between these points. Typically used for single runways with on control point at the high end and one control point at the low end. Therefore, the valid number of controls points is n=2 or n>=9.

EXAMPLE

Name of boundary shapefile:

PASY.shp

Name of control point file is shapefile name + ‘_cpt.txt’:

PASY_cpt.txt

Control point file contents (comma-delimited longitude,latitude,z in meters):

174.080129225473542,52.718193800866999,18.2
174.0795692671567,52.718169454853225,18
174.08062831875597,52.72066492126531,18
174.080117052466647,52.72062840224465,18.2
174.079630132191113,52.720591883223982,18
174.080579626728394,52.723355155787608,17
174.080056187432206,52.723355155787608,17.2

USAGE

1. Select text DSF file.

2. Burn areas of constant elevation (i.e. flat runways)?, default=YES

3. If YES to burn areas of constant elevation, select boundary polygon shapefile and enter elevation data field name.

4. Burn sloped runways or areas with varying elevation?’, default=’YES’

5. If YES to burn sloped runways or areas with varying elevation, select boundary polygon shapefile.

6. Optionally choose to recalculate normals for changed vertices.

Updated text DSF is written to source DSF file directory. Source text DSF is retained with ‘_orig’ suffix.