Re: sub-REGIONS of three-arguments (curvilinear) SHADE,FILL,CONTOURandVECTOR

[Jonathan Callahan <callahan@xxxxxxxxxxxxx>]

Emanuele,

You mention the 'applet' so I wonder if you are using Ferret in the
context of LAS?

In any case, you can restrict the region that is plotted using

  shade/hlimits="xlo:xhi"/vlimits="ylo:yhi" temp, lon, lat

The 'hlimits' and 'vlimits' qualifiers specify the range to display in
the output plot and use the output plot axes rather than the I and J
indices associated with the data.

NOTE 1:  The /hlimits qualifier doesn't handle always handle (e/w)
properly for degrees longitude so be sure to use the same sign (+/-)
that is on the axis data.

NOTE 2:  This technique doesn't reduce the amount of data read into
Ferret, only the amount of data plotted so you may have performance
problems plotting tiny regions from huge curvilinear datasets.

Anyway, I hope this works for you.  And let us know if you've set up an
LAS site.

best wishes,


-- Jonathan Callahan



emanuele.lombardi@casaccia.enea.it wrote:
> 
> Dear Ferreters,
> here I am asking again for your help.
> 
> My data is defined on axis which are 2 dimensional. I shade the data
> using
>         yes? set REGION/K=1/L=1
>         yes? SHADE temp, lon, lat
> 
> where lon and lat are 2 dimensional arrays.
> lon    contains nx*ny longitudes
> lat    contains nx*ny latitudes
> temp   contains nx*ny temperatures at each level/time
> 
> Now I would like to shade subregions of the area using X and Y values I
> get from a java applet. For istance, If I want to shade only the area
> which longitudes lies between 10 and 20 degrees_east, I do the following
> 
>         yes? set region/X=10:20/Y=.......
> 
> BUT the X axis doesn't exists for any variable AND I don't know how to
> create it since it should be made up of a bidimensional array of values.
> 
> I'm aware I could define the region using I & J instead of X & Y, but I
> prefere to use directely X and Y values coming from he applet without
> any conversion.
> 
> I see this is a much difficult question than the yesteday's one,
> so I thank you in advance for any help!
> 
> Emanuele
> 
> PS. here the ncdump -h of my file
> 
> netcdf tipo1a {
> dimensions:
>         time = UNLIMITED ; // (13 currently)
>         nz = 40 ;
>         ny = 98 ;
>         nx = 162 ;
> variables:
>         double time(time) ;
>                 time:var_code = 1000 ;
>                 time:long_name = "time" ;
>                 time:short_name = "time" ;
>                 time:units = "hours since 1962-05-10 00:00:00" ;
>                 time:coordinates = "time" ;
>                 time:axis = "T" ;
>         float sigma(nz) ;
>                 sigma:var_code = 5009 ;
>                 sigma:long_name = "vertical sigma level" ;
>                 sigma:short_name = "sigma level" ;
>                 sigma:units = "adim" ;
>                 sigma:coordinates = "nz" ;
>                 sigma:axis = "Z" ;
>        float lat(ny, nx) ;
>                 lat:var_code = 5000 ;
>                 lat:long_name = "latitudine" ;
>                 lat:short_name = "lat" ;
>                 lat:units = "degree_north" ;
>                 lat:coordinates = "nx ny" ;
>                 lat:axis = "Y" ;
>         float lon(ny, nx) ;
>                 lon:var_code = 5001 ;
>                 lon:long_name = "longitude" ;
>                 lon:short_name = "lon" ;
>                 lon:units = "degree_east" ;
>                 lon:coordinates = "nx ny" ;
>                 lon:axis = "X" ;
>         float temp(time, nz, ny, nx) ;
>                 temp:var_code = 10004 ;
>                 temp:long_name = "temperature" ;
>                 temp:short_name = "t" ;
>                 temp:units = "K" ;
>                 temp:coordinates = "time sigma lon lat" ;
> }
> 
> --
> 
> $$$ Emanuele Lombardi
> $$$ mail:  ENEA  CLIM  Casaccia
> $$$        I-00060 S.M. di Galeria (RM)  ITALY
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