[gradsusr] Extract different point values

[Muhammad Yunus Ahmad Mazuki]

If you would like to extract that data, do utilise scripting. It depends on
what are your values concept? is a point value as in just one data, or in
that point, you want a series values, perhaps temperature from 1000 hPa to
850 hPa at a point, or a time series perhaps. In any case, you can extract
what you want from both model and obsservation and compare them in GrADS,
maybe do some analysis using GrADS as well. Example of point value.

'sdfopen foo.nc'
lonvalue=90
latvalue=0
levvalue=850
tvalue=1
'set lon 'lonvalue
'set lat 'latvalue
'set t 'tvalue
'set lev 'levvalue
'd variable1'
catch=sublin(result,4)
'set gxout fwrite'
'set fwrite point.dat'
'd 'catch
'disable fwrite'

This is just a basic one point value extraction. You can expand this based
on your needs. You can use loop in setting the lon, lat, lev and t value,
that is if your interested location can be used in loops. You can read more
on http://www.iges.org/grads/gadoc/script.html for scripting and
http://www.iges.org/grads/gadoc/aboutgriddeddata.html if you wish to
extract a more complicated values (series, timeseries, or even
fields(though you better off opening both model and observational in
GrADS)).

Yunus.

On Tue, Mar 26, 2013 at 2:23 AM, Thomas Robinson <ter at hawaii.edu> wrote:

> Madak,
>
> If you set your latitude and longitude and vertical level to the point you
> want and display the variable, then you can get the point value.
>
> Let's say you want to get precip at 21.2N and 158.8W
> set lat 21.2
> set lon -158.8
> set z 1
> d precip
>
> In the command line, it will display the single point value.
>
> -Tom
>
>
> On Mon, Mar 25, 2013 at 3:05 AM, Mary Ndlovu <maryndlovu at aol.com> wrote:
>
>> I do not think i understand very well. How is your data, montly, daily
>> etc? And what exactly do you want to select, that would make it easier to
>> help if we have the specifications.
>>
>>
>>  Mary Ndlovu
>> maryndlovu at aol.com
>>
>>
>>  -----Original Message-----
>> From: Madak Khan <madak76 at yahoo.com>
>> To: gradsusr <gradsusr at gradsusr.org>
>> Sent: Sun, Mar 24, 2013 12:16 pm
>> Subject: [gradsusr] Extract different point values
>>
>>  Hi
>> I have an output (precipitation) from model in NetCDF format. I want to
>> extract the corresponding values of 30 points how can i do that? these 30
>> points are my selected stations with specific latitude and longitude. I
>> will compare these values (from model output) with observed data. so if any
>> body have script please guide me.
>> Thank you
>> FROM:
>> Madak
>>
>> _______________________________________________
>> gradsusr mailing listgradsusr at gradsusr.orghttp://gradsusr.org/mailman/listinfo/gradsusr
>>
>>
>> _______________________________________________
>> gradsusr mailing list
>> gradsusr at gradsusr.org
>> http://gradsusr.org/mailman/listinfo/gradsusr
>>
>>
>
>
> --
> Tom Robinson
> President - Graduate Student Organization
> Graduate Student - Department of Meteorology
> 732-718-2323
>
> _______________________________________________
> gradsusr mailing list
> gradsusr at gradsusr.org
> http://gradsusr.org/mailman/listinfo/gradsusr
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://gradsusr.org/pipermail/gradsusr/attachments/20130326/9cc9740e/attachment-0003.html