weixj2003ld wrote:
I read a .tif file ,and use the following code to get the MinX,MinY,MaxX
and MaxY of the coordation of the tif image.
...
double *m_AdGeoTransform=new double[6];
poDataset->GetGeoTransform(AdGeoTransform);
nX=poDataset->GetReasXsize();
nY=poDataset->GetReasYsize();
MinX=AdGeoTransform[0];
MinY=AdGeoTransform[3];
MaxX =AdGeoTransform[0]+nX*AdGeoTransform[1]+nY*AdGeoTransform[2];
MaxY=AdGeoTransform[3]+nX*AdGeoTransform[4]+nY*AdGeoTransform[5];
...
I find that MaxY is less than MinY ,why?
Thk u in advance.
Wei,
GeoTransform[3] is the the Y origin, that is the Y value of the top left
corner of the top left pixel. In a normal georeferenced image this is
the north west corner, and since "northing" (Y) increases as you move
to the north the GeoTransform[3] value will generally be the maximum Y
for the image.
So I think you just need to compute:
MaxY = AdGeoTransform[3];
MinY = AdGeoTransform[3] + nX*AdGeoTransform[4]+nY*AdGeoTransform[5];
Best regards,
--
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I set the clouds in motion - turn up | Frank Warmerdam, warmer...@pobox.com
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and watch the world go round - Rush | Geospatial Programmer for Rent
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