[gdal-dev] Problem with nodata values

[Rainer M Krug]

Hi

I have a geotiff and want to use gdalwarp to warp to it into a
different projection.
I do the following:

gdalwarp -s_srs EPSG:32734 -t_srs '+proj=longlat +ellps=WGS84
+no_defs' Outeniqua.tiff Outeniqua_wgs84.tiff

The problem is, that in Outeniqua_wgs84.tiff, the nodata values from
Outeniqua.tiff become translated into -9999. In addition, the areas
new to Outeniqua_wgs84.tiff (due to the warping) become 1.

Which options do I have to use to keep the nodata values and to make
the values of the "new areas" also as nodata values?

Thanks

Rainer
-- 
Rainer M. Krug, Centre of Excellence for Invasion Biology,
Stellenbosch University, South Africa