Re: [ferret_users] shade + plot/vs and curvilinear grid

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

Hi Luiz,
The values need to be numbers, without any W or S designation. I'm 
guessing that this will work:

 shade var,lon,lat
 plot/vs/ov {350,350},{-35,-25}


After you draw the plot with the curvilinear SHADE or FILL command, look at the symbols that describe the longitude and latitude range of the plot axes.

SHOW SYMBOL PPL$XMIN, PPL$XMAX
SHOW SYMBOL PPL$YMIN, PPL$YMAX

Your list of points need to lie within these ranges for them to show up on the plot. That is, PLOT/VS does not automatically add or subtract 360 from the longitudes to match the modulo X axis of the plot (this is true even if we're not in curvilinear coordinates).

If the points are in variables, say xpts and ypts, there's no reason to check them by hand; you could do something like this:

 shade var,lon,lat
 plot/vs/over xpts,ypts
 let xmin = xpts[x=@min]
 let xmax = xpts[x=@max]
 IF `xmin lt ($ppl$xmin)` THEN plot/vs/over/nolab xpts+360,ypts
 IF `xmax gt ($ppl$xmin)` THEN plot/vs/over/nolab xpts-360,ypts





Luiz Alexandre de Araujo Guerra wrote:
> Dear coleagues,
>
> I am trying to make a figure using shade and plot/vs to draw a line but I have
> a problem. My data file is a model output with curvilinear grid. So, I use
> shade with three parameters: "shade var,lon,lat". I want to draw a meridional
> line. I have been tried: "plot/vs/ov {10W,10W},{35S,25S}" or "plot/vs/ov
> {-10,-10},{-35,-25}" and both result an error message. I have already tried:
> "plot/vs/ov {3574,3574},{1037,1182}" (grid model indexes) and nothing happened.
>
> I have read some group messages about the use of @itp transform to draw lines
> in time series figures. I had success with that method and I expected to adapt
> it to my problem... but it didn´t work too.
>
> I was wondering if the Ferret group could help.
>
> Thanks for your attention.
>
> Best regards,
>
> --
> Luiz Alexandre Guerra
> Aluno de Doutorado / Graduate Student
>
> Universidade Federal do Rio de Janeiro / Rio de Janeiro Federal University
> COPPE/PEnO / Ocean Engineering Program
>
>