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[THREDDS #RDT-808100]: Color Palette

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  • Subject: [THREDDS #RDT-808100]: Color Palette
  • Date: Thu, 17 Sep 2009 11:55:47 -0600
Hi Tim,

> Can you explain how the WMS .pal files are defined? For example, what
> do the values mean that are listed?  I know that they are RGB values
> but how do I set it to show fill values as black? Some of the data I am
> using is oceanographic data and the land mask values are set extremely
> low in the dataset and it throws off my color range.

I believe the palette files are just a list of colors upon which the range of 
data values are mapped. They don't specify how fill or missing values are 
displayed.

Instead, by specify missing and fill values and maybe the valid range, you can 
change how the code determines the range of data values. This can be done in a 
few ways. First, if your data is stored in netCDF files (and you can modify 
your data files), you can set some combination of "missing_value", 
"_FillValue", "valid_min", and "valid_max" attributes. If your data is not 
netCDF or you can't modify them, you can add this information in the TDS 
configuration catalogs.

Here's the netCDF page that describes these attributes:

http://www.unidata.ucar.edu/software/netcdf/docs/netcdf/Attribute-Conventions.html

Here's a TDS page on using NcML in the TDS configuration files:

http://www.unidata.ucar.edu/projects/THREDDS/tech/tutorial/NcML.htm

Let us know if you have any more questions.

Ethan

Ticket Details
===================
Ticket ID: RDT-808100
Department: Support THREDDS
Priority: Normal
Status: Closed