[Gdal-dev] GDAL data model, caching, GDALProjDef

Jim Julian julian at preferred.com
Mon Feb 17 12:18:21 EST 2003

Hi Derrick,

    Without the use of an (usually) expensive GIS program you would have to
improvise. You may be better off treating the data in image form. Use GDAL
to convert a DEM for the same quadrangle as your topo to a GeoTiff and
resample to the same SCALE (not the SIZE, check the world files). This will
make the DEM a template with which you can perform unions/intersections
etc. Think of the images as arrays then this will make more sense. You still
need to write or find the software to do these operations, but I don't believe
there is much difficulty. Python has an imaging library(PIL) which might be
of some help.

                                                                   Jim Julian

At 02:08 PM 2/16/03 -0500, you wrote:

>1) Is there a way I'm overlooking to decollar collared maps (in GeoTIFF
>form) or is it expected that an external program would be used for this? I
>understand that the georeferencing is insufficient to know where the image
>corners are, but I have other data which can be used for this.

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