# VISAN Color Table Information

**URL:** https://forum.atmospherictoolbox.org/t/visan-color-table-information/513
**Category:** VISAN
**Created:** [May 22, 2022, 12:27pm UTC](https://forum.atmospherictoolbox.org/t/visan-color-table-information/513 "2022-05-22T12:27:00Z")
**Posts on this page:** 3
**Page:** 1

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### Author: ![NigelG](https://forum.atmospherictoolbox.org/letter_avatar_proxy/v4/letter/n/ea5d25/32.png) [@NigelG](https://forum.atmospherictoolbox.org/u/NigelG)
#### Post date: [May 22, 2022, 12:27pm UTC](https://forum.atmospherictoolbox.org/t/visan-color-table-information/513/1 "2022-05-22T12:27:00Z")

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The VISAN reference documentation states the following with relation to the colortable property for WPLOT :

" The color table to associate with the values in dataset.  
VISAN will first try to see if the value of this string is equal to one of its built-in predefined color tables: “BlackToWhite”, “WhiteToBlack”, “GreenToRed”, “RedToGreen”, “Cloud”, “Rainbow”, “Ozone”, “Blackbody”, or “Aerosol”.  
In all other cases, the string is interpreted as a filename containing a VISAN color table definition."

I can find no reference to the VISAN color table definition in any file or documentation.

Is it possible to import a VISAN color table definition from an external file or export a customized color table to an external file?

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<div class="post-metadata">

### Author: ![sander.niemeijer](https://forum.atmospherictoolbox.org/user_avatar/forum.atmospherictoolbox.org/sander.niemeijer/32/5_2.png) [@sander.niemeijer](https://forum.atmospherictoolbox.org/u/sander.niemeijer)
#### Post date: [May 22, 2022, 8:03pm UTC](https://forum.atmospherictoolbox.org/t/visan-color-table-information/513/2 "2022-05-22T20:03:14Z")

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This indeed is a bit of underdeveloped functionality. Passing a path to a colortable file also doesn’t seem to work.  
What will work is:

```auto
a = wplot(product)
a.GetColorTable(0).Import("colortable.txt")

```

And then use something like this for colortable.txt:

```auto
ColorTable 1.0
TableSize=256
Name=Custom
NumberOfGradientEdges=3
InterPolationMode=0
0.0 0 0 1.0 1.0
0.5 0 1.0 0.0 1.0
1.0 1.0 0 0 1.0

```

Make sure to set NumberOfGradientEdges to the number of XRGBA values you provide at the end.

This should hopefully get you going until we properly fix this.

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<div class="post-metadata">

### Author: ![NigelG](https://forum.atmospherictoolbox.org/letter_avatar_proxy/v4/letter/n/ea5d25/32.png) [@NigelG](https://forum.atmospherictoolbox.org/u/NigelG)
#### Post date: [May 23, 2022, 1:04am UTC](https://forum.atmospherictoolbox.org/t/visan-color-table-information/513/3 "2022-05-23T01:04:04Z")

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Thank you for your prompt reply.

Your solution works for me and gives the functionality that I need.