Re: GO LAND

[Jeremy S Pal <jpal@xxxxxxx>]

  Hi Juan -

I have done this for a rotated mercator projection.  (Jonathan Callahan
helped me through this problem when I first started up on ferret.)  The
procedure was fairly straight forward.

I am not sure what map projection you use.  (I think non equidistant
lat-lon projection is not a specific projection.)  But regardless of the
projection, the procedure should be somewhat straight forward.

There are two or more ways you can do this:

(1) The first and easiest is using the 3-argument SHADE, FILL, or CONTOUR
command, as follows:

   shade my_data, x_page, y_page

where x_page and y_page are the latitude and longitude descriptions of
each data point.  This should plot your data on a standard lat-lon
grid.  Form there, you can run GO LAND.  See
http://ferret.wrc.noaa.gov/Ferret/Documentation/Users_Guide/v50/chapter6.html#V5.0_projection 
for more information.

(2) Now if you want to get fancier, you can also have ferret plot the
country and land/sea borders on top of your data.  This procedure is a bit
more complicated.  The nice thing about this method is that portion of the
map that falls outside of your domain is not plotted.  If you are 
interested method, I am help you through it.  Also, see mp_demo.jnl for a
demo.

(3) You could probably interpolate your data onto a lat-lon grid.  This
may be useful for some purposes (e.g. comparing your model to observations
which are supplied on a lat-lon grid.).  It should also be fairly easy to
implement, but I do not know how to do it.


Let me know if you have any further questions.


  - Jeremy


On Wed, 24 Nov 1999, Juan Antonio Prego wrote:

>     Dear ferreters?
> 
>     Any experience using go land for non equidistant lat-lon projections?
> 
>     Ferret is confused and thinks that X and Y axis are longitude and latitude,
> but they are not, since x=i=1:50 and y=j=1:51. The output is from a REGIONAL model,
> any experience with that?
> 
>     Any suggestion about how to change land.jnl script for non equidistant lat-lon
> projections?
> 
>     Any help would be greatly appreciated.
> 
>     Juan
> 
> 
> 
>