# Custom contour question (long)

```Does anyone know if there is an automatic method of calculating contour levels.
I am thinking of something similar to the PPLUS command %RANGE, which given a
minimum, maximum, and number of increments calculates axis limits
automatically. I would prefer to do this using ferret commands.

My specific usage is that I have a number of variables I wish to contour that
have a close to gaussian distribution but with very long "tails". I can
automatically calculate the mean and standard deviation using ferret. Now, I
would like to contour the variables so that there are 8 levels in the range of
+/- 1 standard deviation from the mean, with 1 level on either side of this
range that includes the  values less than 1 standard deviation and values more
than 1 standard deviation. The problem is that the numbers I get from my mean
and standard deviation calculations would give me a contour command that looks
like this example:

fill/lev=(0.04321226,10.4844942,10.44128194)(10.4844942,41.2065277,3.8402541)(41.2065277,107.9406128,66.7340851)
Var

Not only does this look ludicrous, but it also produces a command that can be
too long to correctly execute, and produces color bar labels that are less than
desirable. In the example above the color bar labels are:

0.0432, 10.5, 14.3, 18.2, 22, 25.8, 29.7, 33.5, 37.4, 41.2, 108

If I could somehow use the PPLUS command %RANGE, and pass the results back to
ferret, or use some method in ferret itself, I could get something that works a
lot better. In the above example, the %RANGE command would give me:

fill/lev=(0.0,10.0,10.0)(10.0,45.0,5.0)(45.0,110.0,65.0) Var

Not exactly what I want (there are only 7 levels in my desired range, not 8),
but it is close enough.

Thanks, Mark

--
-------------------------------------------------------------------------------

Mark Verschell (verschell@coaps.fsu.edu)
Center for Ocean and Atmospheric Prediction Studies
Florida State University
2035 E. Paul Dirac Drive
R.M. Johnson Bldg. - Suite 200
Tallahassee, FL  32310
(904) 644-6532              (904) 644-4841 (fax)

```