National Oceanic and
Atmospheric Administration
United States Department of Commerce

Model outputs with equal-length months

Model outputs with equal-length months


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



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.


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

! 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.