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Re: Reading Images and re-plotting them in different color tables [message #77958] Fri, 14 October 2011 16:13
Michael Galloy is currently offline  Michael Galloy
Messages: 1114
Registered: April 2006
Senior Member
On 10/14/11 2:51 PM, Steve Daal wrote:
> Hi,
>
> what I have seems simple but I am not getting to the bottom of it.
> I have a map image (Earth.png) that is plotted via colortable 39. I
> want to read it in and replot it with another color table, # 7. The
> problem is, read_png gives me an array of [3,600,600] while the
> original image is [600,600] (I know this part), so the color table
> index is embedded in the array.
> read_query confirms this as well, using color_quan doesn't seem to
> help. Any thoughts on this? Thanks in Advance.

Why doesn't COLOR_QUAN help? That's the normal way to convert a
TrueColor image into an indexed color image. Remember that it might not
be exact since your input image might have more colors than a color
table can hold.

Mike
--
Michael Galloy
www.michaelgalloy.com
Modern IDL, A Guide to Learning IDL: http://modernidl.idldev.com
Research Mathematician
Tech-X Corporation
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