Creating a Taylor Diagram

QUESTION: Is it possible to create a Taylor Diagram in IDL?

ANSWER: Yes, it is possible. Fernando Santoro at ExelisVis has done all the hard work for us and made a program named taylor_diag.pro available on the ExelisVis Code Library web page. (Heighted security concerns prevent me from linking to it.) The program is written in the new IDL 8 function graphics system.

I have shamelessly stolen most of the code to create a similar program for those of us who have not yet migrated to IDL 8 and yet still need the Taylor Diagram functionality. In the process of converting this program to Coyote Graphics, I have added a feature or two that I thought was missing in the original code.

Here is an example of how you might create the Taylor Diagram. On-line documentation for the program is available.

   labels = ['A', 'B', 'C', 'D', 'E', 'F', 'G', 'H']            
   stddev = [1.4, 0.9, 1.0, 1.272, 1.1, 0.95, 1.08, 0.5]        
   correlation = [0.8, 0.9, 0.65, 0.74, 0.91, 0.98, 0.85, 0.35] 
   ref_std = 1.0                                                
   stddev_max = 1.5                                             
   cgTaylorDiagram, stddev, correlation, REF_STDDEV=ref_std, $
       STDDEV_MAX=stddev_max, LABELS=labels, OUTPUT='taylordiagram.png'

The result of running the code is shown in the figure below.

A Taylor Diagram in IDL.

Update: New Keywords

Four new keywords, starting with the letters “RMS_” were added to the program on 29 Jyly 2013 to give the user more control over the display and formatting of the RMS contours on the diagram.

Version of IDL used to prepare this article: IDL 8.2.1