[Thread Prev][Thread Next][Index]

Re: [ferret_users] Customized palette

You can write the palette from within Ferret. This is probably not the most elegant solution, but it works:

1) make a one-line file in your Ferret path consisting of the line (I call it "palette_header"):

RGB_Mapping By_Value

2) make a script in your Ferret path with the following lines (I call it "make_centered_palette.jnl"):

sp \rm centered_palette.spk
sp cat palette_header > centered_palette.spk
list/nohead/append/file=centered_palette.spk/format=(4f8.0) `vname[i=@min,j=@min,k=@min,l=@min]-1`,`0`,`0`,`80` list/nohead/append/file=centered_palette.spk/format=(4f8.0) `0`,`90`,`90`,`90` list/nohead/append/file=centered_palette.spk/format=(4f8.0) `vname[i=@max,j=@max,k=@max,l=@max]+1`,`80`,`0`,`0`

3) in your Ferret session (or another script), suppose you want to shade the variable "rose" (e.g. from etopo20, as I tested):

set dat etopo20
let vname=rose
go make_centered_palette.jnl
pal centered_palette
shade rose

I suppose this will fail if there is no zero in the data being shaded ....

Billy K

On Oct 21, 2010, at 1:36 PM, Jian Ma wrote:

Hi Andy,

Thanks! But that (percentage method) only works when you use
lev=(-a,a,b). If 0 is not in the middle of your value range, it does not
work to show 0 as white.


On Thu, 2010-10-21 at 08:59 -0600, Andy Jacobson wrote:
Hi Tony,

Did you try light_centered.spk or white_centered.spk? If you don't like those, my memory is that you can define a palette with just three colors (white and the two endpoints), and ferret will interpolate.


On Wed 20 Oct 2010, at 19:31 , Jian Ma wrote:

Hi All,

There are 3 methods in Ferret to define new pal files. However, I found
no way to define one like this:

White near 0, dark red on maximum, and blue on minimum.

I know I can use blue_darkred to achieve this when I have proper level values or change the percentage values in the pal file, but is there any method to make a universal pal file to self adjust correctly about 0?

The last method is to write a fortran program to generate files, given
particular level values.

Many thanks,

[Thread Prev][Thread Next][Index]

Contact Us
Dept of Commerce / NOAA / OAR / PMEL / TMAP

Privacy Policy | Disclaimer | Accessibility Statement