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

[Even Rouault]

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.tif

Ruth,

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

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