#3586 closed defect (fixed)
gdaldem hillshade azimuth parameter wrongly interpreted
Reported by: | Even Rouault | Owned by: | Even Rouault |
---|---|---|---|
Priority: | normal | Milestone: | 1.7.3 |
Component: | Utilities | Version: | 1.7.0 |
Severity: | normal | Keywords: | gdaldem hillshade azimuth |
Cc: |
Description
Vincent Schut discovered that the azimuth parameter of gdaldem hillshade wasn't interpreted consistently with the documentation.
Instead of 0 = sun at the north, 90 at the east, 180 at the south and 270 at the west, we had 0 degrees is west, 90 is south, 180 is east and 270 is north
This could be easily demonstrated with the following Python script to generate a 4-face pyramid :
import gdal import osr ds = gdal.GetDriverByName('GTiff').Create('testdem.tif', 100, 100, 1) ds.SetGeoTransform([2,0.01,0,49,0,-0.01]) sr = osr.SpatialReference() sr.ImportFromEPSG(4326) ds.SetProjection(sr.ExportToWkt()) for j in range(100): data = '' for i in range(100): val = 255 - 5 * max(abs(50-i),abs(50-j)) data = data + ('%c' % (val)) ds.GetRasterBand(1).WriteRaster(0,j,100,1,data) ds = None
and following gdaldem commandline : gdaldem hillshade testdem.tif testdem_shaded.tif -s 111120 -z 100 -az XXXX
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Fixed in trunk (r19743) and branches/1.7 (r19744)