Data in rotated grid coordinates

[Gudrun Nina Petersen]

Sorry, I'll try again with a more descriptive subject.

------

I have data from the UK Met Office Unified Model (UM) that is in rotated
grid coordinates. My domain is roughly centred on 60N.  North post is brought to
equator to make equal area grid for the calculations.
If I plot the data directly,
the longitude is 18W to 17E and latitude 14S to 32N

However, in reality the data is within the following boundaries

   (75N,120W)-----------------(86N,40W)--------------------(75N,40E)
       |                          |                             |
       |                          |                             |
       |                          |                             |
       |                          |                             |
       |                          |                             |
       |                          |                             |
       |                          |                             |
       |                          |                             |
   (37N,62W)------------------(40N,40W)---------------------(37N,18W)


I've read the documentation on PDEF but I still don't understand how to plot
the data in the correct geographical location.

I can write a pdef-file that contains x(i,j),y(i,j),wrot(i,j), information
about the correct location of each point: e.g. x(1,1)=-62 and y(1,1,)=37.

However, I can't understand how to use my pdef-file in the ctl-file as the
data is not on a linear grid anymore when moved to the north.


Any help would be greatly appreciated.

Best regards,

G. Nina Petersen
School of Environmental Sciences
University of East Anglia
Norwich
UK