Re: [ferret_users] Ternary map

[Russ Fiedler <russell.fiedler@xxxxxxxx>]

Hi Markus,

I think that you need to generate your own colourmap based on values and 
then encode
the information using integer arithmetic.

I'm attaching  a sample (coarse) palette file that give a result similar 
to your attachment.
It requires encoding 2 independent fractional values into a unique 
integer which is associated with a colour.

Run the   TernaryDiagram script which and the define a new variable 
which encodes the fractional values into integers

 go TernaryDiagram.jnl
! mypal has a granularity of 0.2 (i.e. 6 levels)
! We fudge a rounding rather than truncation
let encoded_var = 10*int(fb*5+0.5)+int(fc*5+0.5)
shade/pal=mypal encoded_var

In a real case use your 2 variables rather than fb and fc.

To get more levels you may want to write a script which generates the 
palette automatically

Russ

On 31/07/13 19:25, markus.mingel@xxxxxxxxx wrote:
> Dear Ferrett folks,
>
> I was wondering who knows how to make this map with ferret?!
> I looked at this link: http://www.pmel.noaa.
> gov/maillists/tmap/ferret_users/fu_2007/msg00384.html but it only shows how to
> make the Ternary Diagram.
>
> Best
> Markus

RGB_Mapping By_value
0 100 0 0
1 80 20 0
2 60 40 0
3 40 60 0
4 20 80 0
5 0 100 0
10 80 0 20
11 60 20 20
12 40 40 20
13 20 60 20
14 0 80 20
20 60 0 40
21 40 20 40
22 20 40 40
23 00 60 40
30 40 0 60
31 20 20 60
32 0 40 60
40 20 00 80
41 0 20 80
50 0 0 100