[gdal-dev] gdalwarp produces all black output

[ludwig.hilger]

Hello everybody, 

I am also a newbie and seem to have a similar problem, but cannot get it
solved. I am trying to reproject the following file:
http://www.altmuehlnet.de/~hilger/Test_Smooth_0208_4258.tif
I am using the following line: 
gdalwarp -et 0 -r bilinear -s_srs EPSG:4258 -t_srs EPSG:25832
Test_Smooth_0208_4258.tif Test_Smooth_0208_4258_25832.tif 
The input image is of data type "byte" and has values from 0 to 255. The
Output image has values all 0, so this seems to be some other problem? 

Thank you, any help is very much appreciated, 

Ludwig


>>>gdalinfo -mm shows your input data file has all it's values in the range
518 to 2396. When converted to a 16bit tif, these all fall in a range
that appears black on your screen. You need to rescale the data to fill
the 16bit range. This is easily done with gdal_translate, which is
probably what you want to use anyway, since you're not changing the
projection, only the data format.

gdal_translate -ot Int16 -scale 518 2396 0 32767 n29.dt1 mosaic.tif <<<



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