[gdal-dev] Correct gdalwarp usage from UTM to Equidistant Cylindrical Projection

Frank Warmerdam warmerdam at pobox.com
Tue Jul 15 22:27:24 EDT 2008


Christopher Hunt wrote:
>> It would have been interesting if you could have included the gdalinfo
>> report for the output file so we could easily compare the region to the
>> region described in your metadata.
> Here's the gdalinfo:
> 
> Driver: GTiff/GeoTIFF
> Files: /Volumes/Users HD/Users/huntc/Documents/Class Action Doco/Titan 
> Class/Heathrow/169460-65786.tif
> Size is 3000, 3000
> Coordinate System is `'
> Origin = (609603.500119999982417,5772321.500249000266194)
> Pixel Size = (45.000000000000000,-45.000000000000000)
> Metadata:
>   TIFFTAG_XRESOLUTION=96
>   TIFFTAG_YRESOLUTION=96
>   TIFFTAG_RESOLUTIONUNIT=2 (pixels/inch)
> Image Structure Metadata:
>   INTERLEAVE=PIXEL
> Corner Coordinates:
> Upper Left  (  609603.500, 5772321.500)
> Lower Left  (  609603.500, 5637321.500)
> Upper Right (  744603.500, 5772321.500)
> Lower Right (  744603.500, 5637321.500)
> Center      (  677103.500, 5704821.500)
> Band 1 Block=3000x1 Type=Byte, ColorInterp=Red
> Band 2 Block=3000x1 Type=Byte, ColorInterp=Green
> Band 3 Block=3000x1 Type=Byte, ColorInterp=Blue
> 
> Finally then, here's how my command now looks - is it complete?
> 
>   gdalwarp -s_srs '+proj=utm +zone=30 +datum=WGS84' -t_srs '+proj=eqc 
> +datum=WGS84' -dstalpha -multi 169460-65786.tif out.tif
> 
> (I'm presuming that I don't need to specify the northerly or easterly 
> component because the file contains this as the origin... and also, the 
> origin assumes the top left corner...)
> 
> Thanks again for your help.

Christopher,

Everything looks fine, but I had actually been hoping to see the
gdalinfo report for the *output* file, not the input.  The output
should have a coordinate system attached, so we should actually see
that lat/long corner coordinates in addition to the projected coordinates.

Best regards,
-- 
---------------------------------------+--------------------------------------
I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | President OSGeo, http://osgeo.org



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