[gdal-dev] gdaldem hillshade returns an empty .tif (i.e. everything is 181 (?))

[Ruth Simm]

Hm. Well the prj is 3857 ...but I reprojected it from 4326....would -

I did run this on one tile - came out fine:
gdaldem hillshade DCM_N00E116.tif hillshade_test.tif -compute_edges -z 5 -s 111120 -az 90
but this returned the same result on the global file:

gdaldem hillshade -of GTiff infile_3857.tif hillshade.tif -compute_edges -z 5 -s 111120 -az 90


 


     On Tuesday, June 30, 2015 2:41 AM, Even Rouault <even.rouault at spatialys.com> wrote:
   

 #yiv0977550860 p, #yiv0977550860 li {white-space:pre-wrap;}Le mardi 30 juin 2015 01:20:13, Ruth Simm a écrit :> I ran this command on a completely NORMAL (but large) global .tiff with a> few tiles missing - but nothing else suspicious - and after 40 minutes it> returned a dud file with '181' being the only value. Has this ever> happened to anyone before?> gdaldem hillshade -of GTiff infile.tif hillshd.tifRuth,I guess this might be an issue with the ratio of vertical units to horizontal.http://gdal.org/gdaldem.html#gdaldem_hillshade:-s scale:ratio of vertical units to horizontal. If the horizontal unit of the source DEM is degrees (e.g Lat/Long WGS84 projection), you can use scale=111120 if the vertical units are meters (or scale=370400 if they are in feet) I'd suggest you experiment a bit on a subwindow of your big raster or a subsampled version of it first.Even-- Spatialys - Geospatial professional serviceshttp://www.spatialys.com

  
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