[Gdal-dev] UTM to Lat/Lon

[Frank Warmerdam]

Matthew Harmon wrote:
> - The relationship between source GeoTIFF and destination imagery tiles 
> may be one-to-many or many-to-one.  In other words, one big 500 Meg 
> GeoTIFF may encompass many destination tiles, or one tile may require 
> many GeoTIFF images as input.  Is there an alpha channel or “null” color 
> that can be used for combining images?

Matthew,

Andrey has answered most questions but I would add that there is intended
to be alpha channel support in the new warp api but this is not currently
implemented.  At the programmatic level there are very flexible options for
masking but only limited options available through gdalwarptest at this time.

> - Is there an ARDG / CADRG input module out there anywhere?

Via the OGDI gateway GDAL can read ADRG and CADRG datasets.  Information on
OGDI can be found at:

  http://ogdi.sf.net/

Unfortunately, this doesn't include much detail on how to use the various
format drivers including RPF and ADRG drivers.  If you want to pursue this
angle and can't find enough information on the GDAL OGDI driver page, and the
OGDI pages on sourceforge let me know, and I will prepare examples.

For a quick example, gdalinfo can refer to some CADRG and ADRG data on my
machine using the "filenames":

gltp:/rpf/usr4/mpp1/cadrg/RPF
gltp:/adrg/usr4/mpp1/adrg/TPUS0101

This only works if OGDI support is configured in of course.

Best regards,

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I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
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