[gdal-dev] gdal_translate - ECW format and non-UTM projections

Frank Warmerdam warmerdam at pobox.com
Wed Jun 8 11:44:53 EDT 2011


On 11-06-08 11:30 AM, Armin Burger wrote:
> Jean-Claude
>
> I guess it's not only a problem of gdalinfo but of some parts of GDAL in general dealing with the ECW.
>
> I made some more tests and when I add the options
>    -co DATUM=WGS84  -co PROJ=NUTM32
> to the gdal_translate call then gdalinfo identifies the coordinates correctly afterwards, but then of course the whole projection is set to UTM...
>
> It seems that the default value entered for DATUM is "RAW" and that seems to cause some of the problems afterwards for GDAL. The problem for me is that I need to insert the correct datum and projection using the syntax of ECW, and I don't know if all available datums/projections used e.g. in Europe are supported, and which syntax to use for the available ones.
>
> I found on my Windows installation a file "PcskeyProjDatum.dat" with a few definitions of projection and datum used but this was very limited and covered mainly UTM and NAD. Most European projections and datums were missing in this file.

Armin,

GDAL skips with a file data/ecw_cs.wkt that lists many ECW
projections and datums.  Perhaps it will be helpful.

There are definately problems translating coordinate system
into the ECW dictionary.  A ticket for a particular case
*might* lead to some improvement but it is an iffy process.

Part of the problem in the thread mentioned by Jean-Claude
is that when the coordinate system translation fails GDAL
also gives up on read the georeferencing transform - or at
least I think it used to work this way.  I think there may
have been some recent fixes in this regard.  If not, a ticket
might be appropriate.

Best regards,

> -------- Original-Nachricht --------
>> Datum: Wed, 08 Jun 2011 16:27:22 +0200
>> Von: Jean-Claude Repetto<jrepetto at free.fr>
>> An: Armin Burger<armin.burger at gmx.net>
>> CC: gdal-dev at lists.osgeo.org
>> Betreff: Re: [gdal-dev] gdal_translate - ECW format and non-UTM projections
>
>> Hi,
>>
>> I think there is a bug in gdalinfo, I already noticed this kind of
>> problem, for example
>> <http://osgeo-org.1803224.n2.nabble.com/gdal-dev-corner-coords-in-tif-vs-ecw-td5608144.html>
>>
>> You should file a bug at<http://trac.osgeo.org/gdal/>  .
>>
>> Jean-Claude
>


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