Re: [ferret_users] The @DDC transformation in contour plots

[Ansley Manke <ansley.b.manke@xxxxxxxx>]

Hi Kirsty,
The @DDC can be used on a multi-dimensioned variable, but the variable 
you're trying to FILL is still 3-dimensional, since the result of 
applying @DDC to the time axis still varies in time.  You could do an 
X-T, or Y-T plot,

yes? fill swh[j=60, L=2:28@DDC]   ! or,
yes? fill swh[i=60, L=2:28@DDC]

Or at a particular time,

yes? fill swh[i=60, L=5@DDC]

Ansley

Kirsty Hanley wrote:
> Hi,
>
> I'm using Ferret v5.81 on Solaris. I have a NetCDF file containing a 
> variable, swh, with X=1:120, Y=1:240 at 6 hourly timesteps for 1 year. 
> I want to calculate and produce a contour plot of the time derivative 
> of this variable at each point in space. I tried using the @DDC command:
>
> yes? fill swh[l=2:28@DDC]
>
> but received the following error:
> **ERROR: dimensions improperly specified: must be a 2D region
>
> If I specify a value of X and Y I can produce a line plot of the 
> derivative:
>
> yes? plot/i=60/j=60 swh[l=2:28@DDC]
>
> Can the @DDC command only be used at a single point? If so, how can I 
> calculate the time derivative over the entire region?
>
> Any help much appreciated,
> Kirsty