[gradsusr] Area inside a contour

[Davide Sacchetti]

for what I know with grads you can't calculate the exact area inside a
contour interval. You could achieve that just by the mesh
granularity ... I mean:

* define mesh area in km^2
area=(cdiff(lon,x)/2*3.1416/180*cos(lat*3.1416/180)*6.37e3)*(cdiff(lat,y)/2*3.1416/180*6.37e3)

* get the region of interest (e.g.: T<28C)
'set gxout stat'
'd maskout(area,t-28)

* get the total area: look for "Stats[sum" in the result

hoping it may help
bye bye
Davide

On Wed, 2011-12-14 at 08:14 -0800, tcavazos at cicese.mx wrote:
> Thanks Miguel;
> 
> It looks like it may work if I sum it up inside the loop, rather than
> using the aave.
> 
> Saludos,
> Tereza
> 
> 
> > Hi Tereza, look at the third example in the next link:
> >
> >
> > http://www.iges.org/grads/gadoc/gradfuncconst.html
> >
> >
> > I hope it helps you.
> >
> >
> > ________________________________
> >  De: "tcavazos at cicese.mx" <tcavazos at cicese.mx>
> > Para: GrADS Users Forum <gradsusr at gradsusr.org>
> > Enviado: Martes, diciembre 13, 2011 8:17 P.M.
> > Asunto: [gradsusr] Area inside a contour
> >
> > Hi,
> >
> > Does anyone know how to calculate the area inside a contour interval? For
> > example the area inside the 28oC contour?
> >
> > I will appreciate any hint.
> >
> > Tereza
> >
> >
> > --
> > Tereza Cavazos
> > Departamento de Oceanografia Fisica
> > CICESE
> > Ensenada, Baja California, MEXICO
> > http://usuario.cicese.mx/~tcavazos/
> >
> > _______________________________________________
> > gradsusr mailing list
> > gradsusr at gradsusr.org
> > http://gradsusr.org/mailman/listinfo/gradsusr_______________________________________________
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> > gradsusr at gradsusr.org
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> >
> 
> 

-- 
--> Attenzione cambio indirizzo: davide.sacchetti at arpal.gov.it
--
Davide Sacchetti
Centro Funzionale Meteo Idrologico di Protezione Civile della Regione Liguria
ARPAL Unità Tecnica Complessa di livello Regionale
V.le Brigare Partigiane 2 16121 Genova (I)
tel: +39 010 6437535                    fax: +39 010 6437520
mail: davide.sacchetti at arpal.gov.it     web: www.meteoliguria.it