[gdal-dev] gdal_translate upside down image

[Frank Warmerdam]

Greg Ederer wrote:
> Hi,
> 
> I'm running gdal_translate against a VRT file:
> 
> <VRTDataset rasterXSize="751" rasterYSize="801">
>   <GeoTransform>-20.05, 0.1, 0.0, 40.05, 0.0, -0.1</GeoTransform>
>   <SRS>
>         GEOGCS[&quot;WGS 84&quot;,
>             DATUM[&quot;WGS_1984&quot;,
>                     SPHEROID[&quot;WGS 84&quot;,6378137,298.2572235630016,
>                             AUTHORITY[&quot;EPSG&quot;,&quot;7030&quot;]],
>                     AUTHORITY[&quot;EPSG&quot;,&quot;6326&quot;]],
>             PRIMEM[&quot;Greenwich&quot;,0],
>             UNIT[&quot;degree&quot;,0.0174532925199433],
>             AUTHORITY[&quot;EPSG&quot;,&quot;4326&quot;]]
>   </SRS>
>   <VRTRasterBand dataType="Float32" band="1" subClass="VRTRawRasterBand">
>     <SourceFilename 
> relativetoVRT="1">10day_precip.bin.1999121</SourceFilename>
>     <ImageOffset>0</ImageOffset>
>     <PixelOffset>4</PixelOffset>
>     <LineOffset>3004</LineOffset>
>     <ByteOrder>MSB</ByteOrder>
>     <NoDataValue>-999.0</NoDataValue>
>   </VRTRasterBand>
> </VRTDataset>
> 
> I just noticed that the resulting GeoTIFF is upside down.  Is this a 
> problem with my GeoTransform values?  If so, what values would produce 
> the image right side up?

Greg,

I don't see any obvious problem with the geotransform values.

Perhaps the image really is upside on disk.  If so, you could flip it as
it is read by changing your values to

<ImageOffset>2403200</ImageOffset>
<PixelOffset>4</PixelOffset>
<LineOffset>-3004</LineOffset>

Best regards,
-- 
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I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
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