Re: Remapping variables onto new axes

```Hi David,

You will find write-ups on this in the demo script

yes? depth_to_density_demo.jnl

and the FAQ at

http://tmap.pmel.noaa.gov/ferret/FAQ/data_management/sigma_coordinate_demo.html

Note that Ferret V4.5 (to be released soon) will have simpler solutions to this
class of problems ... but the solutions presented in the documents above are
quite workable.

Happy Ferreting - steve

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On Sep 10, 11:06am, David Oxilia wrote:
> Subject: Remapping variables onto new axes
> I have a netCDF file which contains oceanographic data. The result of a
> 'show data' in Ferret is:
>
>  name     title                             I         J         K         L
>  UP       Baroclinic zonal velocity        1:275     1:307     1:10      1:9
>  VP       Baroclinic meridional velocity   1:275     1:307     1:10      1:9
>  DP       Layer thickness                  1:275     1:307     1:10      1:9
>  UB       Barotropic zonal velocity        1:275     1:307     1:10      1:9
>  VB       Barotropic meridional velocity   1:275     1:307     1:10      1:9
>  ETA      Bottom pressure variation        1:275     1:307     1:10      1:9
>  US       Zonal forcing of barotropic      1:275     1:307     1:10      1:9
>  VS       Meridional forcing of barotropi  1:275     1:307     1:10      1:9
>  Q        Barotropic Montgomery function   1:275     1:307     1:10      1:9
>
> Here, DP are increments in pressure at each ocean layer k=1:10. The axes
> which result from plotting vertical sections are either latitude(theta) vs
> Z(layer) or longitude(phi) vs Z(layer).
>
> In order to plot a section of incremental pressure (as a function of Z) I
> created a variable, P, as follows:
>
> repeat/k=1:9 let P = (1+eta)*dp[k=@rsum]
>
> A couple of questions:
>
> - Is it possible to create variables like P omitting the 'repeat' statement
>   making more effective use of the @ notation?
>
> - Is there a way to invert P(Z) to obtain Z(P)?
>
> - How can I plot sections of UP or VP as function of P rather than Z?
>   This would provide sections of dynamic variables as a function of
>   'depth' rather than the non-dynamic Z.
>
> Many thanks,
>
> David.
>
> *-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
> David Oxilia                          Tel: (541) 737-2368
> COAS-Oregon State University          Fax: (541) 737-2064
> Corvallis, OR 97331-5503              Email: oxilia@hejira.oce.orst.edu
> *-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
>-- End of excerpt from David Oxilia

```