[Gdal-dev] UTM to Lat/Lon

[Tyler Mitchell]

Matthew,
I haven't reprojected rasters with gdal before, but I did use the osr.py
python module to reproject some GPS point data from geographic to UTM.  I
can provide an example of this in my python-based GPS->PostGIS conversion
program if you are interested.

That said, I'm not sure that you must use WKT.  If I'm not mistaken, you
could also use EPSG numbers to specify your source and destination
projections.  You need to have the PROJ libraries setup and working, which
is the only dependency I know of.  But I find them so easy to use because
you can simply use a number (i.e. EPSG:4326) to specify your reference
systems, rather than a lengthy hard-to-read WKT method :]

Hope that helps you enjoy the blessing of GDAL.

Tyler

gdal-dev-admin at remotesensing.org wrote on 09/03/2003 12:22:51 PM:

> I’m a total newbie, so please excuse me if this is obvious.
>
> I need to create a tool to convert GeoTIFF in UTM to image tiles in
> geographic (lat/lon) projection.  It looks like the Warp API will do
> the trick for me, but I have a few questions.
>
> -          How do I set up the output coordinate system correctly?
> It appears I need to supply a WKT for the destination coordinate
> system, but I don’t know how to set this up for geographic.
> -          I’m looking at the “GDAL Warp API Tutorial” as well as
> the source to gdalwarp and gdalwarp test.  Is this the place to be
looking?
>
> That should get me going… however; I have other complicating issues
> that I’d love to hear people’s suggestions on.
>
> - 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?
>
> - Is there an ARDG / CADRG input module out there anywhere?
>
> Thanks for any hints/suggestions!