[gdal-dev] getcolortable is null

[weixj2003ld]

Thk u for your detail reply.
1.Now,I have a DEM(.img) file,and its band number is 1.When I use 'gdal_translate  -b 1 -of  PNG old.img new.png' to create a png file(I think its contains height map infomation,is it?).the error 'Warning 6:PNG driver doesn't support data type Int16.Only eight bit<Byte>' and sixteen bit<Uint16> bands supported.Defaulting to Byte.
2.When I use 'gdal_translate -b 1 -of JPEG old.img new.jpg',the error 'JPEG doesn't support data type Int16. Only eight and twelve bit bands supported<Mk1 libjepg>'
 
happy every day.



>weixj2003ld wrote:
>> 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
>
>Wei,
>
>This will require programming or scripting.   It cannot be done
>with the stock commandline tools.
>
>> 2. what is the general combination for good look jpeg file?
>
>That depends greatly on the source sensor and the goals of the visualization.
>A 4,2,1 b  false color band combination is common with Landsat imagery,
>butit can be disputed whether it looks good or not.  Also, constrast
>stretching is often also desirable on satellite imagery for best
>visualization.
>
>Best regards,
>
>-- 
>---------------------------------------+--------------------------------------
>I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
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>
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