[Gdal-dev] question about AsciiGrid

Norman Vine nhv at cape.com
Fri Apr 15 14:39:58 EDT 2005


Frank Warmerdam writes:
> 
> On 4/15/05, jluis at ualg.pt <jluis at ualg.pt> wrote:
> > Hi,
> > I think this is closly related to my early post
> > 
> > http://xserve.flids.com/pipermail/gdal-dev/2005-March/008269.html
> > 
> > The metadata solution seams a good idea to solve this grid vs pixel
> > registration
> > or "pixel is area" vs "pixel is point" issue.
> 
> Joaquim, 
> 
> But I think in the case of your post, the netCDF driver has failed to 
> "adjust" things to the GDAL pixel-is-area model properly because I didn't
> realize the netCDF was pixel-is-point.  The important part to solve that
> problem is to fix the driver to adjust the extents properly.   As a secondary
> issue, the driver could return metadata indicating if the pixels should be
> interpreted as points or areas. 

Frank 

GMT '.grd. files can be either 'line' or 'pixel' oriented

see the "node_offset" member in the GRD_HEADER struct

This is in "gmt_grd.h"

http://gmt.soest.hawaii.edu/gmt/doc/html/GMT_Docs/node144.html

HTH

Norman



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