[R] making a grid of points

Roger Bivand Roger.Bivand at nhh.no
Thu Dec 7 20:32:56 CET 2006


On Thu, 7 Dec 2006, Ross Boylan wrote:

> I'd like to evaluate a function at each point on a 2 or 3-D grid.  Is
> there some function that already does this, or generates the grid of
> points?
> 
> My search has led me to the grid and lattice packages, and I found a
> reference to the sp package (e.g., SpatialGrid) for this.  There are
> things in there that might be relevant, but at first blush many of them
> are embedded in other concepts (grobs, shingles, rugs) and don't
> obviously solve the problem.
> 
> I know this is not a hard thing to program, but I suspect someone has
> already done it.  Any pointers?

Which "space" are your points in? The sp package might help if the data 
are spatial/geographical, but I think that expand.grid() is your friend, 
followed by one of the apply() family to run your function on each row of 
the data frame output by expand.grid().

Roger


> 
> Thanks.
> 

-- 
Roger Bivand
Economic Geography Section, Department of Economics, Norwegian School of
Economics and Business Administration, Helleveien 30, N-5045 Bergen,
Norway. voice: +47 55 95 93 55; fax +47 55 95 95 43
e-mail: Roger.Bivand at nhh.no




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