ogxp_spline_surface_preview.py

DESCRIPTION

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 control points is n=2 or n>=9.

This program is useful for previewing surface that will be created in DSF mesh via ogxp_basemesh.py.

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

Select boundary shapefile.

Output spline surface GeoTIFF is written to source shapefile directory with ‘_spline’ suffix.

spline_pre1

spline_pre2