making a grid of points
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