[gdal-dev] Re: gdal_translate changes coordinate system

[Hermann Peifer]

Frank Warmerdam wrote:
> Hermann Peifer wrote:
>> [peifer at whitefish:lceugr100_06]> gdalinfo lceugr100_06_pct.tif
>> Driver: GTiff/GeoTIFF
>> Files: lceugr100_06_pct.tif
>>        lceugr100_06_pct.aux
>> Size is 67000, 58000
>> Coordinate System is:
>> PROJCS["ETRS_1989_LAEA_L52_M10",
>>     GEOGCS["GCS_ETRS_1989",
>>         DATUM["European_Terrestrial_Reference_System_1989",
>>             SPHEROID["GRS_1980",6378137.0,298.257222101]],
>>         PRIMEM["Greenwich",0.0],
>>         UNIT["Degree",0.0174532925199433]],
>>     PROJECTION["Lambert_Azimuthal_Equal_Area"],
>>     PARAMETER["False_Easting",4321000.0],
>>     PARAMETER["False_Northing",3210000.0],
>>     PARAMETER["Central_Meridian",10.0],   <---
>>     PARAMETER["Latitude_Of_Origin",52.0], <---
>>     UNIT["Meter",1.0]]
> ...
>> [peifer at whitefish:lceugr100_06]> gdalinfo template.tif
>> Driver: GTiff/GeoTIFF
>> Files: template.tif
>> Size is 1000, 1000
>> Coordinate System is:
>> PROJCS["ETRS_1989_LAEA_L52_M10",
>>     GEOGCS["GCS_ETRS_1989",
>>         DATUM["European_Terrestrial_Reference_System_1989",
>>             SPHEROID["GRS 1980",6378137,298.2572221010042,
>>                 AUTHORITY["EPSG","7019"]],
>>             AUTHORITY["EPSG","6258"]],
>>         PRIMEM["Greenwich",0],
>>         UNIT["degree",0.0174532925199433]],
>>     PROJECTION["Lambert_Azimuthal_Equal_Area"],
>>     PARAMETER["latitude_of_center",0],  <--
>>     PARAMETER["longitude_of_center",0], <--
>>     PARAMETER["false_easting",4321000],
>>     PARAMETER["false_northing",3210000],
>>     UNIT["metre",1,
>>         AUTHORITY["EPSG","9001"]]]
> 
> Hermann,
> 
> The problem appears to be that for the first file the coordinate system
> is being read from the .aux file, but not properly converted from ESRI
> format to OGR format.  So the parameters should be named latitude_of_center
> and longitude_of_center but instead are still using the ESRI names of
> Central_Meridian and Latitude_Of_Origin.  The GeoTIFF writer does not
> notice these values and writes default zeros for the lat/long of center
> parameters in the geotiff file and that is what you get on read back.
> 
> I believe this is a failure of the .aux file reading logic to normalize
> the coordinate system properly. Looking in the morphFromESRI() code there
> appears to be handling for this transformation, so I suspect it is subtly
> broken, or not being invoked by the .aux reader.
> 
> Could you file a ticket with the .aux file, and information on the version
> of GDAL you are using?
> 
> As a work around you could paste the WKT with the zero lat/long of center
> into a file (your_edited.wkt), edit in the correct values, and then
> add "-a_srs your_edited.wkt" to the gdal_translate command.
> 
> But please do file the ticket - I'd like to fix this if the problem still
> exists.
> 
> Best regards,

Thanks for the workaround. It works. Any hint why -a_srs EPSG:3035 made 
things worse?

BTW, I am using GDAL 1.6.0, released 2008/12/04

Hermann