Ref Sec20.
PALETTE
Alias for PPL SHASET SPECTRUM=. Specifies or restores the default color. PALETTE is also implemented as a qualifier for the 2-Dimension graphics commands FILL, CONTOUR/FILL, SHADE, and POLYGON commands.
yes? PALETTE pal_name
or
yes? FILL/PALETTE=pal_name var yes? SHADE/PALETTE=pal_name var yes? POLYGON/PALETTE=pal_name var
The argument is the name of a palette file. Many palettes are included in the Ferret distribution. Try the Unix command "Fpalette '*'" to see a list of available palette files.
Some of the palettes are designed for particular needs. "centered.spk", for example, emphasizes the contrast between positive and negative shade levels. "land_sea.spk" uses blue tones for negative values and browns and greens for positive values, making it suitable for topography displays.
Palette files end in the file suffix .spk, but the suffix is not necessary when specifying a palette. Use GO try_palette pal_name to display a palette. The GO files "exact_color.jnl" and "squeeze_colors.jnl" can be used to modify palettes. You can also create new palette files with a text editor. See the chapter "Customizing Plots", section "Shade and fill colors" for the format of a palette file.
PALETTE with no argument restores the default palette. When you use the qualifier /PALETTE= in conjunction with /SET_UP, PPLUS makes the specified color spectrum the new default palette, and all subsequent shaded or color-filled plots will use that palette as the default. To restore the previous palette to the default, use PALETTE with no argument after your customization.
To assist you in choosing a good palette for your plot, there is an FAQ, How can I find a good color palette for my plot?