[Gdal-dev] Question about gdal_translate and the bridge/gateway

[Christiansen, Kevin (Contractor)]

Hello, hello!

I have a question about the gltp bridge when used with gdal_translate.exe
and gdal_merge.py.  I am using 'OpenEV_FW_171.zip', dated 4-5-2004, on a
Windows 2000 Professional box with a gig of ram.

I am attempting to use them to translate between ADRG format and GeoTiff
format.  A typical command line that I am using looks like this:

gdal_translate -of GTiff
gltp:/adrg/C:/Kevin/NH1206/TLUS0101:"TLUS0101.IMG":Image out.tif

The output of this command is:
Input file size is 15616, 11136
0...10...20...30...40...50...60...70...80...90...100 - done.

This does generate a (679 Megabyte) 'out.tif' file, which is indeed 15616 x
11136 pixels in size. Unfortunately, there is only 1000 x 1000 pixels worth
of data in that file.  In other words, the output file looks like a 1000 x
1000 pixel image that was expanded / zoomed to 15616 x 11136 pixels - it's
very, very blocky.  Note that if I use gdal_merge.py (instead of
gdal_translate) to translate the ADRG image to GeoTiff, I get the same
behavior.

If I ask 'gdalinfo' about the file (via "gdalinfo
gltp:/adrg/C:/Kevin/NH1206/TLUS0101"), the output starts with the following:

Driver: OGDI/OGDI Bridge
Size is 1000, 1000
Coordinate System is:
GEOGCS["unnamed ellipse",
<etc>

Based on that "Size is 1000, 1000" line, I am guessing that the ADRG reader
is reading in the 15616 x 11136 pixel image and then squishing it down to
1000 x 1000 pixels so that it will fit through the OGDI bridge / OGDI
gateway. After the (squished) image passes through the bridge/gateway, the
GeoTiff writer then expands the image back to its full 15616 x 11136 pixel
resolution before it writes it to the output file.  Unfortunately, most of
the image data is lost in this process.

Are there any parameters, registry entries, environment variables, source
code changes, etc. that I can use to tell gdal_translate and/or gdal_merge
to increase the 'size' of the bridge/gateway so that the ADRG reader can
pass the full-size image to the GeoTiff writer, so I don't have this data
loss?

Thank you VERY much for any help you can give me in this matter!

- Kevin Christiansen