Re: [ferret_users] Re: [ferret_users] plot a variable according to altitude

[Francois Delclaux <francois.delclaux@xxxxxxxxxxxxxxxxxxx>]

Hi Patrick,

Thanks for your reply.

Yes, I know conditionnal variables. But in my case, I have too many Z0 
values in my DEM, so, I can't do this computation manually for each Z0.

Regards

François

Le 07/09/2016 15:57, Patrick Brockmann a écrit :
>   
> Le Mercredi 7 Septembre 2016 10.31 CEST, Francois Delclaux <francois.delclaux@xxxxxxxxxxxxxxxxxxx> a écrit:
>   
> > Hi Ferret users,
> >
> > I have a DEM Z(x,y) and a map precipitation P(x,y)
> >
> > Now I would like to plot (or save in a ascii file), for each cell which
> > has the same elevation, the average of all the  precipitation values
> > which are at this elevation.
> > In other word, for a given Z0 elevation, I would like to have the
> > average of Precipitation values which are at Z0 elevation.
> >
> > What the best way for doing that ?
> Hi François,
>
> Are you aware of conditionnal variables in ferret ?
>
> You can easilly define a mask on a variable by selecting a specific value (or range)
> Then multiply this mask with the quantity to analyze and
> then list the average.
>
> An example using levitus_climatology
>
> yes? use levitus_climatology
> yes? let mask = if salt gt 35 and salt le 37 then 1
> yes? let temp_at_mask = temp * mask
> yes? list temp_at_mask[i=@ave,j=@ave,k=1]
> you get 22.86
>
> Hope that will help
> Regards
>
> Patrick
>
>   

--
Francois DELCLAUX
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