making a grid of points

Thu, Dec 7, 2006 11:03 AM #

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?

Thanks.

Ross Boylan                                      wk:  (415) 514-8146
185 Berry St #5700                               ross at biostat.ucsf.edu
Dept of Epidemiology and Biostatistics           fax: (415) 514-8150
University of California, San Francisco
San Francisco, CA 94107-1739                     hm:  (415) 550-1062

Roger Bivand

Thu, Dec 7, 2006 11:32 AM #

On Thu, 7 Dec 2006, Ross Boylan wrote:

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

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