<DIV>Thk u for your detail reply.</DIV>
<DIV>1.Now,I have a DEM(.img) file,and its band number is 1.When I use 'gdal_translate&nbsp; -b 1 -of&nbsp; 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&lt;Byte&gt;' and sixteen bit&lt;Uint16&gt; bands supported.Defaulting to Byte.<BR>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&lt;Mk1 libjepg&gt;'</DIV>
<DIV>&nbsp;</DIV>
<DIV>happy every day.</DIV>
<DIV></DIV><BR><PRE><BR>&gt;weixj2003ld&nbsp;wrote:
&gt;&gt;&nbsp;Thk&nbsp;u&nbsp;very&nbsp;much.
&gt;&gt;&nbsp;I&nbsp;have&nbsp;two&nbsp;questions.
&gt;&gt;&nbsp;1.If&nbsp;I&nbsp;want&nbsp;to&nbsp;use&nbsp;the&nbsp;following&nbsp;combination,
&gt;&gt;&nbsp;Red=Band3
&gt;&gt;&nbsp;Green=Band2*0.8+band4*0.2;
&gt;&gt;&nbsp;Blue=band1
&gt;
&gt;Wei,
&gt;
&gt;This&nbsp;will&nbsp;require&nbsp;programming&nbsp;or&nbsp;scripting.&nbsp;&nbsp;&nbsp;It&nbsp;cannot&nbsp;be&nbsp;done
&gt;with&nbsp;the&nbsp;stock&nbsp;commandline&nbsp;tools.
&gt;
&gt;&gt;&nbsp;2.&nbsp;what&nbsp;is&nbsp;the&nbsp;general&nbsp;combination&nbsp;for&nbsp;good&nbsp;look&nbsp;jpeg&nbsp;file?
&gt;
&gt;That&nbsp;depends&nbsp;greatly&nbsp;on&nbsp;the&nbsp;source&nbsp;sensor&nbsp;and&nbsp;the&nbsp;goals&nbsp;of&nbsp;the&nbsp;visualization.
&gt;A&nbsp;4,2,1&nbsp;b&nbsp;&nbsp;false&nbsp;color&nbsp;band&nbsp;combination&nbsp;is&nbsp;common&nbsp;with&nbsp;Landsat&nbsp;imagery,
&gt;butit&nbsp;can&nbsp;be&nbsp;disputed&nbsp;whether&nbsp;it&nbsp;looks&nbsp;good&nbsp;or&nbsp;not.&nbsp;&nbsp;Also,&nbsp;constrast
&gt;stretching&nbsp;is&nbsp;often&nbsp;also&nbsp;desirable&nbsp;on&nbsp;satellite&nbsp;imagery&nbsp;for&nbsp;best
&gt;visualization.
&gt;
&gt;Best&nbsp;regards,
&gt;
&gt;--&nbsp;
&gt;---------------------------------------+--------------------------------------
&gt;I&nbsp;set&nbsp;the&nbsp;clouds&nbsp;in&nbsp;motion&nbsp;-&nbsp;turn&nbsp;up&nbsp;&nbsp;&nbsp;|&nbsp;Frank&nbsp;Warmerdam,&nbsp;warmerdam@pobox.com
&gt;light&nbsp;and&nbsp;sound&nbsp;-&nbsp;activate&nbsp;the&nbsp;windows&nbsp;|&nbsp;http://pobox.com/~warmerdam
&gt;and&nbsp;watch&nbsp;the&nbsp;world&nbsp;go&nbsp;round&nbsp;-&nbsp;Rush&nbsp;&nbsp;&nbsp;&nbsp;|&nbsp;Geospatial&nbsp;Programmer&nbsp;for&nbsp;Rent
&gt;
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