Re: [ferret_users] Problem with southern polar stereographic plot

[Ansley Manke <ansley.b.manke@xxxxxxxx>]

Hi Martin,
It's a question of the order of operations. Put the "GO mp_grid" before 
the go mp_aspect and the set region, and it'll work fine. (or use SET 
GRID SST instead of mp_grid.jnl).  mp_stereographic_south defines the 
mapping variables based on pseudo-variables "X" and "Y".  Until Ferret 
knows what grid these are going to be coming from, it assumes they're 
from the abstract axes X and Y, which have values X=1,2,3,... and 
Y=1,2,3...  So the region y=-90:0 can't be applied to that,. and the 
error comes in mp_aspect which tries to use the mapping variables to set 
up the window.

 use coads_climatology
  go mp_stereographic_south
  go mp_grid sst
  set region/x=0:360/y=-90:0/l=1
  go mp_aspect
  fill/nolab/nokey/noaxes sst, x_page, y_page

or

 use coads_climatology
  go mp_stereographic_south
 set grid sst
  set region/x=0:360/y=-90:0/l=1
  go mp_aspect
  fill/nolab/nokey/noaxes sst, x_page, y_page


Martin Dix wrote:

> I get an error when trying to do a southern polar stereographic plot.
> The following example is essentially from mp_demo.jnl
>
> use coads_climatology
> ! NH version works
> ! set region/x=0:360/y=0:90/l=1
> ! go mp_stereographic_north
> ! SH version fails
> set region/x=0:360/y=-90:0/l=1
> go mp_stereographic_south
> go mp_aspect
> go mp_grid sst
> fill/nolab/nokey/noaxes sst, x_page, y_page
>
> The NH version works as expected. The SH version gives
>
> **ERROR: illegal limits: "X_PAGE[I=@MAX,J=@MA..." is not in the range
> Y=-90:0
>          Axis extremes are Y=0.5:10000000
> DEFINE VARIABLE/quiet x_axis_range = `x_page[i=@max,j=@max]` -
> `x_page[i=@min,j=@min]`
> Command file, command group, or REPEAT execution aborted
>
> I'm using
>        FERRET v5.81
>        Linux(g77) 2.4.21-32 - 07/13/05
>
> I also get the same error with
>        FERRET v5.70
>        Linux(g77) 2.4.18 - 06/30/04
>
> Regards
>
> Martin Dix