[gdal-dev] gdalwarp for ED50 UTM zone 31N to WGS84

[Ragi Y. Burhum]

Gracias Jorge

2009/5/13 Jorge Arévalo <jorge.arevalo at gmail.com>

> Hello,
>
> I'm from Spain, and I can confirm your parameters. These worked for me as
> well.
>
> Regards
> Jorge
>
>
> On Tue, May 12, 2009 at 1:03 AM, Ragi Y. Burhum <ragi at burhum.com> wrote:
>
>> I was just sending this e-mail so that it can be searched through the
>> archives. Thanks to Even Rouault for walking me through something that
>> should have been obvious :)
>>
>> Originally, I was having trouble finding the right parameters for gdalwarp
>> to be able to warp some imagery that I got from Spain. These were in ED50 /
>> UTM zone 31N:
>>
>> rburhum at cuzconix:~/p_bug$ gdalinfo exported_from_original_sid_file.tif
>> Driver: GTiff/GeoTIFF
>> Files: exported_from_original_sid_file.tif
>> Size is 6946, 4800
>> Coordinate System is:
>> PROJCS["ED50 / UTM zone 31N",
>>     GEOGCS["ED50",
>>         DATUM["European_Datum_1950",
>>             SPHEROID["International 1924",6378388,297.0000000000014,
>>                 AUTHORITY["EPSG","7022"]],
>>             AUTHORITY["EPSG","6230"]],
>>         PRIMEM["Greenwich",0],
>>         UNIT["degree",0.0174532925199433],
>>         AUTHORITY["EPSG","4230"]],
>>     PROJECTION["Transverse_Mercator"],
>>     PARAMETER["latitude_of_origin",0],
>>     PARAMETER["central_meridian",3],
>>     PARAMETER["scale_factor",0.9996],
>>     PARAMETER["false_easting",500000],
>>     PARAMETER["false_northing",0],
>>     UNIT["metre",1,
>>         AUTHORITY["EPSG","9001"]],
>>     AUTHORITY["EPSG","23031"]]
>> Origin = (327720.000000000000000,4730783.500000000000000)
>> Pixel Size = (0.500000000000000,-0.500000000000000)
>> Metadata:
>>   AREA_OR_POINT=Area
>> Image Structure Metadata:
>>   INTERLEAVE=PIXEL
>> Corner Coordinates:
>> Upper Left  (  327720.000, 4730783.500) (  0d53'46.94"E, 42d42'34.10"N)
>> Lower Left  (  327720.000, 4728383.500) (  0d53'49.56"E, 42d41'16.35"N)
>> Upper Right (  331193.000, 4730783.500) (  0d56'19.50"E, 42d42'36.88"N)
>> Lower Right (  331193.000, 4728383.500) (  0d56'22.08"E, 42d41'19.12"N)
>> Center      (  329456.500, 4729583.500) (  0d55'4.52"E, 42d41'56.62"N)
>> Band 1 Block=6946x1 Type=Byte, ColorInterp=Red
>> Band 2 Block=6946x1 Type=Byte, ColorInterp=Green
>> Band 3 Block=6946x1 Type=Byte, ColorInterp=Blue
>>
>>
>> In order to get it to work correctly, I had to use the right +towgs84
>> parameters from
>> http://earth-info.nga.mil/GandG/coordsys/onlinedatum/CountryEuropeTable.html. Although the table showed  -84 (+/-5), -107(+/-6), -120 (+/-3), for my own
>> purposes -87, -98, -121 seemed to work best based on my source data.
>>
>> so the command line would be:
>>
>>  gdalwarp -s_srs "+proj=utm +zone=31 +ellps=intl +units=m
>> +towgs84=-87,-101,-121 +no_defs" -t_srs EPSG:4326
>> exported_from_original_sid_file.tif testout.tif
>>
>> Hope this helps someone else,
>>
>> - Ragi
>>
>>
>>
>>
>>
>>
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>>
>
>
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