Greg Ederer wrote:
...
Note that the pixel/line coordinates in the above are from (0.0,0.0) at
the top left corner of the top left pixel to
(width_in_pixels,height_in_pixels) at the bottom right corner of the
bottom right pixel. The pixel/line location of the center of the top
left pixel would therefore be (0.5,0.5).
</end docs>
But, I'm still unsure how to compute the required values. The docs
don't give units for GT(1) and GT(5), and for GT(0) and GT(3). My data
have a resolution of 0.1 deg lat X 0.1 deg lon, and the upper left
lat/lon is 40N,20W. Could you give me some pointers on how to compute
the transform values?
Greg,
The geotransform coordinate system is whatever is defined by the <SRS>
tag. So in your case I believe long/lat WGS84.
I imagine your GeoTransform would be:
-20.05, 0.1, 0.0, 40.05, 0, 0.1
This is assuming that the upper left corner really reflects the center
of the top left pixel in which case a half pixel offset is needed. I'm
also assuming north up image orientation.
Best regards,
--
---------------------------------------+--------------------------------------
I set the clouds in motion - turn up | Frank Warmerdam, [email protected]
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush | Geospatial Programmer for Rent
_______________________________________________
gdal-dev mailing list
[email protected]
http://lists.osgeo.org/mailman/listinfo/gdal-dev
