[gdal-dev] getcolortable is null

[weixj2003ld]

Thk u very much.
I have two questions.
1.If I want to use the following combination,
Red=Band3
Green=Band2*0.8+band4*0.2;
Blue=band1
2. what is the general combination for good look jpeg file?



>weixj2003ld wrote:
>> I read a geotiff file, and find that
>> poBand->GetColorTable()==NULL
>
>Wei,
>
>Presumably GetColorTable() returns NULL because the GeoTIFF file
>does not have a color table.
>
>> But I use ERDAS IMAGINE9.2 (a software that deal with geotiff), I find 
>> that it is not grey,but I use "gdal_translate -b 6 -of JPEG old.tif 
>> net.jpg", find that is is grey.
>
>Well, you are selecting only one band withouta color table to export
>to net.jpg.  How do you expect it to be anything other than greyscale?
>If you want an RGB jpeg file then select three bands to be used as
>red, green and blue.
>
>eg.
>gdal_translate -b 4 -b 5 -b 6 o-of JPEG  old.tif net.jpg
>
>Best regards,
>
>-- 
>---------------------------------------+--------------------------------------
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>
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