Hi
Thank you for that resource, Patrick.
Once you have the outline and have verified it using
PLOT/VS, Patrick's message shows how to use the POLYGON
command to plot the shape. Another option is the
function pt_in_poly,
http://ferret.pmel.noaa.gov/Ferret/documentation/users-guide/appendix-a-external-functions/pt_in_poly/
which would let you make a mask which is 1 at every grid
location inside the polygon and missing outside it; so
you could do calculations or graphics over only the
region inside the border.
Ansley
On 2/7/2012 11:29 AM, Brockmann Patrick wrote:
> nitin patil a écrit :
>> Dear ferret users,
>> Did any one knows
how to give a border to India country if we have to plot
only India.
>> if possible can we border states also?
>
> Hi,
>
> I have done this recently using kml files
distributed
> by the "Global Administrative Areas" website.
>
> Please follow the different steps:
>
> 1) From
http://www.gadm.org
> Go in the Download section, select the country
> and choose "Google Earth .kmz"
>
> After the download, you can have a look to the kmz
file
> with googleearth of course.
> Unzip the kmz file. You should obtain a kml file.
>
> 2) Convert the kml file to a text with
> 3 columns lon,lat,number (number is the
> index representing the area) with the python
> script attached.
>
> 3) Use the ferret plot.jnl script to validate and
> save the polygons as a netcdf file.
>
> Here is an example with India with the first
> 2 administratives levels.
>
> $ unzip IND_adm1.kmz
> $ ./convert_kml.py IND_adm1.kml > IND_adm1.dat
> $ ferret
> yes? go plot.jnl IND_adm1.dat
IND_adm1.nc
>
> Note: that when I try to do the same with
IND_adm0.dat,
> ferret restarts my X11 server !
> The problem occurs at line
> repeat/name=n/range=1:`numb[i=@max]` ( def sym
n=`n` ; let lon1=if numb eq `n` then lon ; let lat1=if
numb eq `n` then lat ;
polygon/line/fill/o/nolab/lev=(1,200,1)/pal=thirty_by_levels.spk
lon1,lat1,`n` ; PPL SHASET RESET )
>
> But the method is still ok, just do not not blindly
> use polygon command but rather plot/vs.
> There may be a problem anyway.
>
> Happy ferreting
>
> Patrick
>