# [ncl-talk] how to get the real lat/lon value after areal calculation?

Guido Cioni guidocioni at gmail.com
Thu Jun 2 03:15:53 MDT 2016

```Hey,
I would suggest to use dim_avg_n instead of dim_avg, so that you can have the control on what you are exactly doing. I think (but maybe I’m wrong) that with your syntax you only get a zonal average, while you want to have a full lat/lon average: is this correct? In order to keep metadata I also suggest to use the _Wrap option.

T_new=dim_avg_n_Wrap(T(:,{minlat:maxlat},{minlon:maxlon}), (/1,2/) )

The (/1,2/) specifies that you are averaging over coordinates lat and lon, on the subset defined by extents {minlat:maxlat},{minlon:maxlon}. Please note that in the output you will get a variable with only time dimension. Thus, I don’t really understand your second question: lat/lon coordinates are not available anymore, since you took a mean over a square.
Cheers

Guido Cioni
http://guidocioni.altervista.org <http://guidocioni.altervista.org/>

> On 02 Jun 2016, at 10:16, dyjbean at 163.com wrote:
>
> hi,
>    i have a variable named T with dimension (lev,lat,lon), and i gave the minlat,maxlat,minlon,maxlon for some zone,
> after i have used function dim_avg with  T_new=dim_avg(T(:,{minlat:maxlat},{minlon:maxlon}))),i obtained the required new variable T_new ,
> but how can i  know the real lat/lon value in T_new, the start and end points are equal to minlat,maxlat or adjacent value from them?
>
>
> dyjbean at 163.com <mailto:dyjbean at 163.com>
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