No subject

[parcranfield]

I have been investigating GDAL and OpenEV having been very pleased to 
find the combination of Python and GIS. In the latest OpenEV release 
1.4.1 there is the capability to read ECW compressed files (Windows 
only) which particularly interests me. I tried this but is there a 
problem with the data/colours displayed ?

I used gdal_translate to extract a test image as below

D:\junk>gdal_translate -srcwin 80000 210000 1000 
1000 "ecwp://217.169.46.98/images/uk/Ordnance_Survey/os_50k_gb.ecw" 
test2.tif

But then comparing the image in OpenEV with the original as displayed 
using the distributed ERViewer program the colours are clearly 
different (the image displayed by ERViewer is correct). Is OpenEV or 
gdal doing some image enhancement automatically ? I tried to open the 
ECW URL directly in OpenEV but unfortunately openev (windows 
version ?) appends the drive automatically - I don't know how to 
override this.

Staying with my image I tried the 3D drape option (using a sample of 
local dem data), but now the ecw image only displays in grey scale, I 
guess an unrelated problem. I also noticed that the default scaling 
on altitude does not appear to be unity as the GUI suggests, it must 
be something much greater.

As a newcomer to OpenEV /GDAL these could all be just problems of my 
own making, any suggestions or help would be most welcome.

Thanks

Phil.