Re: [ferret_users] india boundary

[jagadish karmacharya <j_karmacharya@xxxxxxxxx>]

Hi Ansley,

Mine is version 6.5.

I have to ask system administrator for the update but that could take ages. Is it possible to install/load it in the version I am currently using?

Thanks

 

Jagadish

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From: Ansley Manke <ansley.b.manke@xxxxxxxx>
To: jagadish karmacharya <j_karmacharya@xxxxxxxxx>
Cc: "ferret_users@xxxxxxxx" <ferret_users@xxxxxxxx>
Sent: Wednesday, February 8, 2012 4:15 PM
Subject: Re: [ferret_users] india boundary

Hi Jagadish,
The function pt_in_poly is included with Ferret versions 6.67 and higher.  Perhaps you have an older Ferret version?  Can you update your Ferret executable?

Ansley

On 2/8/2012 4:59 AM, jagadish karmacharya wrote:

Hi Patrick and Ansley,

Thanks a lot but I am a bit confused. My guess is direct application of Patrick's methode would be mask (white out) unwanted regions surrounding Area Of Interest (AOI) that a mask of AOI itself. However, method mentioned by Ansley should make suppliment it and make it possible to creat a mask for AOI upon which averages etc. could also be computed.

Well, I followed the steps mentioned by Patrick ( took a while to figure out, plot.jnl is the script he has written in this mail) for NPL_adm0. Firstly, margins_set.jnl script is missing in my case, so at first I just disabled that line. This produced the filled map for Nepal with seemed OK. Next I replaced the margins_set.jnl script with margins.jnl; but this time filled map and the boarder outline does not overlay. Does is makes any difference? the resulting nc file seems to overlay correctly (with both plot/vs and polygen) when I tried it over another dataset (as well as match with go land overlay. 

Furhter, Patrick, what do you mean by: " .... just do not blindly use polygon command but rather plot/vs. There may be a problem anyway."

My prime interest is to creat a mask for AOI, but I can't find pt_in_poly function (It is not listed when I issue show function command). Can someone send me a copy?

Thanks in advance.

Jagadish

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From: Ansley Manke <ansley.b.manke@xxxxxxxx>
To: Brockmann Patrick <Patrick.Brockmann@xxxxxx>
Cc: nitin patil <nitinpatil85@xxxxxxxxx>; ferret_users@xxxxxxxx
Sent: Tuesday, February 7, 2012 10:43 PM
Subject: Re: [ferret_users] india boundary

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
>