[gdal-dev] using GIO driver to create grids

[Frank Warmerdam]

Andrew.Loughhead at c... wrote:
> 
> Thanks for the suggestion Frank. The same thing does seem 
> to happen in gdal_translate. Some details follow...
> 
> I have made a small test grid in Grid with demshd(), which is 
> to say that its an integer grid, and that its values are in 
> the range 52-248. This is called dshd. Then:
> 
> gdal_translate.exe -of GTiff -ot byte dshd dshd.tif
> Size is 260, 237
> 0.Band 1 Type = 5
> ..10...20...30...40...50...60...70...80...90...100 - done.
> 
> and the result is good (loads in Photoshop, looks fine). 
> Then to try the reverse:
> 
> gdal_translate.exe -of GIO -ot Float32 dshd.tif gdal_dshd
> Size is 260, 237
> 0.Band 1 Type = 1
> ..10...20...30...40...50...60...70...80...90...100 - done.
> 
> and I end up with a grid, it lists in arcinfo, a describe in 
> arcinfo shows it as having min=0.0, max=248.0, and of course 
> its a Floating Point grid, as GDAL doesn't yet write Integer 
> grids. However, when drawn or interrogated, the grid gdal_dshd 
> is all nodata. If I make a new grid from it with 
> Grid: gdal_dshd2 = int(gdal_dshd), Grid reports that all cells 
> in the new grid are nodata. 
> 
> I'm using gdal-1.1.6, built with MSVC 6, avgridio.dll is from 
> Arcview3.2. 
> 
> Anything more I can try to diagnose this? 

Andrew,

I will try this out today, and see if I can reproduce the problem.

Best regards,

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