[Gdal-dev] Finding the row and column in a Raster that includes a point

[Frank Warmerdam]

On Tue, 8 Feb 2005 15:19:28 -0600, Johnson,  Donald W MVK Contractor
<Donald.W.Johnson at mvk02.usace.army.mil> wrote:
> This appears to work. However by closly examining my output files I have
> found the calculated row position is inncorrect. The row value is initaly
> correct for points whose y value is near prj[3] however the r value is
> increasingly over estimated as the y value of p[i] moves away from prj[3].
> Can anyone tell what I am doing wrong?

Donald, 

I don't know why this would be wrong.  My guess would be that there
is something wrong with the geotransform for your file.  How much is it off
by the time to get to the bottom off the image?  One pixel?  Much more? 

 
> Also does GDAL have issues with large files? RasterIO returns CPL_Failure
> when I try to read and ESRI grid that is 3.7 gigs. The code works fine on
> smaller surfaces.

Some formats use the "large file api" and support large files.  Others do
not.  The Arc/Info binary grid format does not currently support files larger
than 2GB.  If you were to provide me a sample of such a grid on a DVD 
I would be willing (eventually) to update the grid code to use the large
file API.  

Best regards,
-- 
---------------------------------------+--------------------------------------
I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | Geospatial Programmer for Rent