National Oceanic and
Atmospheric Administration
United States Department of Commerce

Model outputs with equal-length months

Model outputs with equal-length months

Question:

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

Example:


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 canstand the (quite) small errors in the placement of the month tics on the plotaxis 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
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 outthe appropriate date for the 120th point. The @ASN only can "associate" thepoints which actually exist -- 120 of them.