<DIV>Thk u very much.</DIV>

<DIV>I have two questions.</DIV>

<DIV>1.If I want to use the following combination,</DIV>

<DIV>Red=Band3</DIV>

<DIV>Green=Band2*0.8+band4*0.2;</DIV>

<DIV>Blue=band1</DIV>

<DIV>2. what is the general combination for good look&nbsp;jpeg file?<BR></DIV>

<DIV></DIV><BR><PRE>&gt;weixj2003ld&nbsp;wrote:

&gt;&gt;&nbsp;I&nbsp;read&nbsp;a&nbsp;geotiff&nbsp;file,&nbsp;and&nbsp;find&nbsp;that

&gt;&gt;&nbsp;poBand-&gt;GetColorTable()==NULL

&gt;

&gt;Wei,

&gt;

&gt;Presumably&nbsp;GetColorTable()&nbsp;returns&nbsp;NULL&nbsp;because&nbsp;the&nbsp;GeoTIFF&nbsp;file

&gt;does&nbsp;not&nbsp;have&nbsp;a&nbsp;color&nbsp;table.

&gt;

&gt;&gt;&nbsp;But&nbsp;I&nbsp;use&nbsp;ERDAS&nbsp;IMAGINE9.2&nbsp;(a&nbsp;software&nbsp;that&nbsp;deal&nbsp;with&nbsp;geotiff),&nbsp;I&nbsp;find&nbsp;

&gt;&gt;&nbsp;that&nbsp;it&nbsp;is&nbsp;not&nbsp;grey,but&nbsp;I&nbsp;use&nbsp;"gdal_translate&nbsp;-b&nbsp;6&nbsp;-of&nbsp;JPEG&nbsp;old.tif&nbsp;

&gt;&gt;&nbsp;net.jpg",&nbsp;find&nbsp;that&nbsp;is&nbsp;is&nbsp;grey.

&gt;

&gt;Well,&nbsp;you&nbsp;are&nbsp;selecting&nbsp;only&nbsp;one&nbsp;band&nbsp;withouta&nbsp;color&nbsp;table&nbsp;to&nbsp;export

&gt;to&nbsp;net.jpg.&nbsp;&nbsp;How&nbsp;do&nbsp;you&nbsp;expect&nbsp;it&nbsp;to&nbsp;be&nbsp;anything&nbsp;other&nbsp;than&nbsp;greyscale?

&gt;If&nbsp;you&nbsp;want&nbsp;an&nbsp;RGB&nbsp;jpeg&nbsp;file&nbsp;then&nbsp;select&nbsp;three&nbsp;bands&nbsp;to&nbsp;be&nbsp;used&nbsp;as

&gt;red,&nbsp;green&nbsp;and&nbsp;blue.

&gt;

&gt;eg.

&gt;gdal_translate&nbsp;-b&nbsp;4&nbsp;-b&nbsp;5&nbsp;-b&nbsp;6&nbsp;o-of&nbsp;JPEG&nbsp;&nbsp;old.tif&nbsp;net.jpg

&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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