Data on land only

[Joerg Kaduk <joerg@xxxxxxxxxxxxxxxxxxx>]

Hi everybody,
I'm really new to Ferret and so I've missed the solution to my problem
in the docu or somewhere else... however after having leaved through
whatever I could find I'm still somewhat unclear how to approach the
following problem:
I plan a to run a model on the land area on the globe only (say 1 deg.)
resolution. This gives you about 15.000 gridelements on the underlying
regular grid going from -180 to 180 E, -90 to 90 N. For storage reasons
I want to save data only on the land points - on the ocean area I'don't
do anything - in netCDF if possible. I would prefer to write the variables
just as a one dimensional array - running through the land grid elements. 
And I'd like to use ferret to visualize the data. Now my question is
can I tell ferret where to locate the data on the globe? I can store
the latitudes and longitudes for the grid elements in a seperate file -
preferably again just as a array running through the land points again in the
same sequence as my other data.
I think a more generic question would be: How do I tell ferret that the
data in a file are on some unregular mask of a regular grid only? If I store
a land mask alonag with the data in the netCDF file?
Finally I could imagine the following trick could work somehow: I save my
data running from south to north and west to east. Then in each band along
longitudes there would be some ocean areas. For each ocean area I'd just 
save one missing value point and save in the netCDF file somewhere how 
long (longitudewise) my grid points are. This way one could make up a
rectengular grid where some elements were very long ( the pacific is along
the equator quite large...) How would I do this such that ferret would
recognise this from the netCDF file without having to have a grid file 
spefified?  I'd really like to avoid having to specify some structure
external to the netCDF files...
Thanks for your patience and time everybody
regards,
Joerg
--
joerg@jasper.stanford.edu