Re: @MAX

[Ansley Manke <Ansley.B.Manke@xxxxxxxx>]

Hi Vincent,
The @MAX transformation does not take an argument, so your
:2 is ignored by Ferret.  If you say "list var[x=@MAX]"  Ferret will
return a single value, the maximum valid data value over the region
that is currently in effect.  If you use it as a regridding transformation,
it returns the maximum value of the original variable within each grid
box of the destination grid (or axis).  I am guessing this is what you are
trying.  Here is an example that will show you how @MAX works.

    ! regrid a variable to coarser axes

   yes? USE coads_climatology
   yes? SET REGION/Y=40/L=1
   yes? LIST sst[X=@MAX]  ! The @MAX transformation

    ! Define two output axes to use
   yes? DEF AXIS/X=140:200:8/UNITS=lon x10
   yes? DEF AXIS/X=140:200:16/UNITS=lon x20

    ! Plot the original data and curves with @MAX regridding
   yes? PLOT/X=140:200/LINE/SYM=27 sst
   yes? PLOT/OVER/LINE/SYM=20 sst[GX=x10@MAX]
   yes? PLOT/OVER/LINE/SYM=18 sst[GX=x20@MAX]

Also compare what it looks like with @MIN instead, or with
@AVE and @LIN regridding.

Vincent Le Fouest wrote:

> Dear Ferret users,
> By default, @MAX will browse the maximum value of a field at each 15th
> point of the grid. I tried to decrease it to less than 15 points, using
> @MAX:2 for instance, but it does not work.
> Do you know something about this?
> Thanks in advance,
> Bye,
> Vincent
>
> --
> Vincent LE FOUEST
> Étudiant au doctorat conjoint en océanographie
> Laboratoire de modélisation numérique
> Institut des sciences de la mer de Rimouski (ISMER)
> 310 allée des Ursulines, Rimouski, Québec, Canada G5L 3A1
> Tel: (418) 723 1985 ext. 1873
> Fax: (418) 724 1842

--
Ansley Manke  Pacific Marine Environmental Laboratory  Seattle WA  (206)526-6246