Re: [ferret_users] samplexy_curv function

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

Hello again,
I've just looked more closely at your script. It looks like there is an 
error in the definition of the variables lonrct and latrct. 
   define axis/x=46:55:0.0555 xaxrct  !163
   define axis/y=36:48:0.0450 yaxrct  !268
   let lonrct=x[gx=xaxrct]
   let latrct=y[gy=yaxrct]

lonrct has 163 points, and latrct has 268.  Do you in fact want to 
sample the data at all of the intersections of xaxrct and yaxrct?  If 
so, you might want to look into the curvilinear regridding functions 
CURV_TO_RECT_MAP and CURV_TO_RECT .

Or, to use samplexy_curv, you need to define the x and y sample points 
in both dimentions as

   let lonrct=x[gx=xaxrct] + 0*y[gy=yaxrct]
   let latrct= 0*x[gx=xaxrct + y[gy=yaxrct] 
( To see what this does, try the command  "yes? plot/vs lonrct, latrct")

and then use reshape or  xsequence before calling the function.

Ansley

Ansley Manke wrote:

> Hi Munrat,
> I don't see anything wrong with what you've done, but a simpler way to 
> put your x and y points on a one-dimensional grid is to use XSEQUENCE 
> function.  This unravels a variable onto an abstract x axis.  Try it 
> this way:
>
> ....
> file/var="lon,lat,depth"/grid=outgrid/col=3 "grid_x162_y267.dat"
>
> let myxpts=xsequence(lonrct)  !one dimensional list
> let myypts=xsequence(latrct)
>
> let temprect=SAMPLEXY_CURV(temp,lon[d=1],lat[d=1],myxpts,myypts)
>
> fill temprect[k=10,l=1]
>
>
> Murat Gunduz wrote:
>
> > Dear Ferret users,
> >
> > I have a POM model output file in curvilinear grid. I wan to convert 
> > it in
> > rectilinear coordinate and plot the variables. I am using 
> > SAMPLEXY_CURV function
> > for this purpose.
> >
> > My variable`s dimensions in curvilinear coordinate are
> >
> > yes? show grid temp
> > GRID GRX5
> > name       axis              # pts   start                end
> > X            X                  162 r   1                    162
> > Y            Y                  267 r   1                    267
> > Z             Z                  16 r     1                    16
> > TIME     TIME            5 r      02-JAN-2000 00:00    06-JAN-2000 00:00
> >
> > I am geting Curvilinear latitude and longitude of this variable from 
> > an ascii file as below.
> > define axis/x=1:162:1 xax
> > define axis/y=1:267:1 yax
> > let outgrid=x[gx=xax]+y[gy=yax]
> > file/var="lon,lat,depth"/grid=outgrid/col=3 "grid_x162_y267.dat"
> >
> >
> > I generate new rectilinear coordinate by
> > define axis/x=46:55:0.0555 xaxrct  !163
> > define axis/y=36:48:0.0450 yaxrct  !268
> > let lonrct=x[gx=xaxrct]
> > let latrct=y[gy=yaxrct]
> > define axis/x=1:`163*268`:1 xyrct
> > let outgridxy=x[gx=xyrct]
> > let myxpts=reshape(lonrct,outgridxy)  !one dimensional list
> > let myypts=reshape(latrct,outgridxy)
> >
> > and using samplexy_curv function
> > let temprect=SAMPLEXY_CURV(temp,lon[d=1],lat[d=1],myxpts,myypts)
> >
> > when I fill the temprect
> > fill temprect[k=10,l=1]
> >
> > it gives the below error:
> >
> > Bailing out of external function "samplexy_curv":
> >        Arguments 4 and 5 must be 1-dimensional lists of equal length
> > **ERROR: : error in external function
> >
> >
> > Do you know, what can be the reason?, Thank you very much in advance.
> > Regards,
> > Murat