[ferret_users] curvilinear data and coordinates units

[Bruno Levier <bruno.levier@xxxxxxxxxxxxxxxxx>]

Hi Ferreters

Be careful when using curvilinear data to have the coordinates units 
properly defined, otherwise the resulting plots can be faulty (Ferret 6.82).

Here is an example. I want to plot a global variable centered on the 
Pacific Ocean (curvilinear grid ORCA). I define a new longitude.

!! Longitude definition (without units)
Let nav_lon_bis = IF nav_lon LT 24 THEN nav_lon + 360 ELSE nav_lon
Shade my_var, nav_lon_bis, nav_lat

The result (see fig1.gif) is bad.

!! Longitude definition (with units)
Let /Units=lon nav_lon_bis = IF nav_lon LT 24 THEN nav_lon + 360 ELSE 
nav_lon
Shade my_var, nav_lon_bis, nav_lat

The result (see fig2.gif) is good.

This problem happens with Ferret 6.82, but not with Ferret 6.2

Bruno Levier

Attachment: fig1.gif
Description: GIF image

Attachment: fig2.gif
Description: GIF image