[MITgcm-support] help to determine the global index

[Jean-Michel Campin]

Hi, 

> yes I read the manual several time and still can't figure out.
> Please give me some hints if anyone has experience.
> thanks.
> Hong

Well, it works exactly as laid out in this figure:
> >   http://mitgcm.org/pelican/online_documents/node164.html

(50,76) will be on tile (3,3): i=50-24*(3-1)=2 ; j=76-28*(3-1)=20
and also in the overlap region of tile (2,3): i=50-24*(2-1)=26 ; j=20.

And I am not sure I understand this:
> > > I checked XC and YC, unfortunately they are not consistent with
> > > global I,J because I use a rotated coordinate system.
since usualy, I used them to find the location of a point,
whatever the grid is.

Jean-Michel

> > > Hi, there
> > > I have problem trying to determine the global index of (I,J)
> > > from tile index (i,j,bi,bj).
> > > My gridding configuration is as follows:
> > >      &           sNx =  24,
> > >      &           sNy =  28,
> > >      &           OLx =   3,
> > >      &           OLy =   3,
> > >      &           nSx =   1,
> > >      &           nSy =   1,
> > >      &           nPx =   4,
> > >      &           nPy =   4,
> > > For example I want to locate the global point (50,76).
> > > How can I find this point?
> > > I checked XC and YC, unfortunately they are not consistent with
> > > global I,J because I use a rotated coordinate system.
> > 
> > Hi Hong,
> > 
> > I've subscribed you to the MITgcm-support list.  And in answer to your
> > question, theres a nice diagram and explanation of the global/local
> > indexing scheme in Chapter 4 of the manual:
> > 
> >   http://mitgcm.org/pelican/online_documents/node164.html
> > 
> > Ed