Hello, I'd like to make a z(x,y) plot for irregularly spaced x,y. What are routines are available in R for this purpose? Thanks, Mark
plotting image/contour on irregular grid
3 messages · m p, Roger Bivand, Roger Koenker
On Fri, 6 May 2005, m p wrote:
Hello, I'd like to make a z(x,y) plot for irregularly spaced x,y. What are routines are available in R for this purpose?
One possibility is to interpolate a regular grid using interp() in the akima package, then use image() or contour(). Another is to use levelplot() with formula z ~ x + y in the lattice package, and the equivalent contourplot(); here, the x,y pairs must lie on a grid, but do not need to fill the grid (so are regularly spaced with missing grid cells).
Thanks, Mark
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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
On May 6, 2005, at 2:45 PM, Roger Bivand wrote:
On Fri, 6 May 2005, m p wrote:
Hello, I'd like to make a z(x,y) plot for irregularly spaced x,y. What are routines are available in R for this purpose?
One possibility is to interpolate a regular grid using interp() in the akima package, then use image() or contour(). Another is to use levelplot() with formula z ~ x + y in the lattice package, and the equivalent contourplot(); here, the x,y pairs must lie on a grid, but do not need to fill the grid (so are regularly spaced with missing grid cells).
You could also try tripack and rgl.triangles to produce piecewise linear surfaces on the Delaunay triangulation of the x,y points. Roger