[Gdal-dev] gdalwarp changes colortable

[acangi]

I forgot to mention I was viewing the rasters with GeoServer and Openlayers.
Thanks for your suggestion, I tested them on QuantumGIS and there the colors
are fine.

So, I guess I just have to forward my question to the geoserver mailing
list, which isn't using OpenEV, AFAIK.


Chaitanya kumar CH wrote:
> 
> acangi,
> 
> Could you check if the after image shows any different colors with
> some other image viewer like ImageMagick? OpenEV might not be reading
> the color table correctly.
> 
> -- 
> Chaitanya kumar CH.
> 
> On Mon, Feb 16, 2009 at 7:43 PM, acangi <aca at ngi.be> wrote:
>>
>> Subscription problem, reposting as requested.
>>
>>
>> acangi wrote:
>>>
>>> Hello,
>>>
>>> I try to translate colormapped geotiff files from EPSG:31300 to
>>> EPSG:3812,
>>> using
>>>
>>> $ gdalwarp -s_srs EPSG:31300 -t_srs "+proj=lcc +lat_1=49.83333333333334
>>> +lat_2=51.16666666666666 +lat_0=50.79781500000000
>>> +lon_0=4.359215833333335
>>> +x_0=649328.0 +y_0=665262.0 +ellps=intl +units=m +no_defs" top250r.tif
>>> top250r_warp.tif
>>>
>>> Using -t_srs EPSG:3812 gives a "is this a valid coordinate system ?"
>>> Using -t_srs 3812.prj (file containing the WKT, taken from
>>> http://spatialreference.org/ref/epsg/3812/ogcwkt/
>>> http://spatialreference.org/ ) gives a "No translation for Lambert Conic
>>> Conformal (2SP) to PROJ.4 is known"
>>> As I couldn't find the PROJ.4 syntax for this SRS, I built it based on
>>> data from the WKT.
>>>
>>> Coordinates transformation seems to work fine, but my colors are wrong:
>>>
>>>
>>> Before :  http://n2.nabble.com/file/n2334758/before.jpeg
>>> After :  http://n2.nabble.com/file/n2334758/after.jpeg
>>>
>>> Checking the files with gdalinfo, I see differences :
>>>
>>> Size is 18300, 15000 ==> Size is 18301, 15001
>>> The projection, the origin and the corner coordinates change like
>>> expected
>>> Pixel Size = (16.666670000000000,-16.666699999999999) ==> Pixel Size =
>>> (16.666302967680906,-16.666302967680906)
>>> Metadata:
>>>   AREA_OR_POINT=Area
>>>
>>> TIFFTAG_DOCUMENTNAME=\\backstage\jobcontainer1\symb\map250\tiff\plot_complet.tif
>>>   TIFFTAG_SOFTWARE=Barco Graphics TIFFOut V1.0.2
>>>   TIFFTAG_XRESOLUTION=381
>>>   TIFFTAG_YRESOLUTION=381
>>>   TIFFTAG_RESOLUTIONUNIT=2 (pixels/inch)
>>> ==> Metadata:
>>>   AREA_OR_POINT=Area
>>> Image Structure Metadata:COMPRESSION=LZW  INTERLEAVE=BAND ==> Image
>>> Structure Metadata: INTERLEAVE=BAND
>>> Band 1 Block=256x256 Type=Byte, ColorInterp=Palette ==> Band 1
>>> Block=18301x1 Type=Byte, ColorInterp=Palette
>>> The color table is the same.
>>>
>>> I tried with some more options : -of GTiff -co "PROFILE=GeoTIFF" -co
>>> "INTERLEAVE=PIXEL" -co "COMPRESS=LZW" -co "TILED=YES" :
>>> Size is 18300, 15001
>>> Yet another Pixel Size
>>> I get the "COMPRESSION=LZW"
>>> and Band 1 Block=256x256 Type=Byte, ColorInterp=Palette
>>>
>>> ...but the colors are still wrong.
>>>
>>> Any idea how I can change the projection without affecting the colors ?
>>>
>>>
>>
>> --
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>> http://n2.nabble.com/gdalwarp-changes-colortable-tp2334758p2335001.html
>> Sent from the GDAL - Dev mailing list archive at Nabble.com.
>>
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> 

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