[R-sig-Geo] transform xy grid references

[Barry Rowlingson]

On Thu, Feb 2, 2012 at 10:14 AM, Jakob Petersen <jpeterb at essex.ac.uk> wrote:
> I have a dataset like this
>
> Id,x,y,grid
>
> 1,2,3,a
>
> 2,5,7,b
>
> And would like to transform the xy from grid b to grid a, like this:
>
> Id,x,y,grid,xa,ya
>
> 1,2,3,a,2,3
>
> 2,5,7,b,17,21
>
> Any suggestions? Many thanks,Jakob
>

 I've stared at this for ten minutes and my suggestion is that you
tell us where the 17 and 21 come from. Is there some formula you've
neglected to tell us?

Barry