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Model outputs with equal-length months


Question:

How can I plot model output with equal-length months?

Example:

[Output Graphic]

Explanation:

This is a problem only in the GRAPHICS. The underlying graphics code, PLOT+, can only create "real" calendar axes ... unequal month lengths. However, Ferret is happy to work computationally with anything you like.

Solution:

If you can stand the (quite) small errors in the placement of the month tics on the plot axis here's an example of how you can work with your equal-month model.
! ************************************
! say your model variable looked like this
define axis/t=30:3600:30/unit=days tmodel       ! 120 equal 30-day months
define grid/t=tmodel gmodel
let my_model_variable = SIN(T[g=gmodel]/100)
plot my_model_variable
message         ! pause

! then you can map it to a real calendar axis as follows
define axis/t=15-jan-1985:15-jan-1995/npoints=121 tcalendar
define grid/like=gmodel/t=tcalendar gcalendar
plot my_model_variable[g=gcalendar@asn]
! *************************************
I used the trick of defining a 121 month axis so I didn't have to figure out the appropriate date for the 120th point. The @ASN only can "associate" the points which actually exist -- 120 of them.


Last modified: Nov 12, 1996