[gdal-dev] using GIO driver to create grids
Frank Warmerdam
warmerdam at p...
Fri Apr 5 09:09:05 EST 2002
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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I set the clouds in motion - turn up | Frank Warmerdam, warmerdam at p...
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush | Geospatial Programmer for Rent
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