gsn_merge_colormaps

Merges two color maps and sets this as the color map for the given workstation.

Prototype

load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl"

	procedure gsn_merge_colormaps (
		wks     [1] : graphic,  
		color_map1  ,           
		color_map2              
	)

Arguments

A Workstation identifier. The identifier is one returned either from calling gsn_open_wks or calling create to create a Workstation object.

The two color maps to merge. They can be string arrays of named colors, arrays grep of red/blue/green (RGB) triplets, and/or predefined color maps.

Description

This procedure merges two color maps and sets this as the new color map for the given workstation.

If the second color map is a list of RGB values or a predefined color map, then the foreground and background colors will be dropped from this color map before it is appended to the first color map. If the second color map is a list of named colors, then all of the named colors will be appended.

Since there's a limit of 256 colors in a colormap, the sum total of colors in the two color maps must be less than or equal to 256.

You can use the gsn_draw_colormap procedure to draw the color map (mostly for debugging purposes).

See Also

gsn_define_colormap, gsn_retrieve_colormap, gsn_reverse_colormap, gsn_draw_colormap, gsn_draw_named_colors

Examples

load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl"

begin
  wks = gsn_open_wks("ncgm","gsn_merge_colormaps")
;
; Merge two pre-defined colormaps;
;
  gsn_merge_colormaps(wks,"rainbow","gsdtol")
  gsn_draw_colormap(wks)

;
; Generate grayscale color map.
;
  gcmap = new((/11,3/),float)
  gcmap(:,0) = ispan(0,10,1)/10.
  gcmap(:,1) = gcmap(:,0)
  gcmap(:,2) = gcmap(:,0)
;
; Append grayscale map to the end of a Blue-White-Red color map.
;
  gsn_merge_colormaps(wks,"BlWhRe",gcmap)
  gsn_draw_colormap(wks)
end

For some application examples, see:

• "color_9.ncl" (view example)

See also the suite of color examples.