On Sun, 21 Dec 2003, Spencer Graves wrote: > Have you considered "interp", as in the following example:
in the akima package, just to make this plain. > > XY <- expand.grid(x=1:11, y=1:11) > XY$z <- XY$x+XY$y > contour(interp(XY$x, XY$y, XY$z)) > > hope this helps. spencer graves > > Thomas W Blackwell wrote: > > >Dear L Z - > > > >Before using contour() one needs to interpolate the z values > >to all points in a rectangular grid. 2D interpolation is not > >trivial. The package KernSmooth (case-sensitive) will do this > >for a density estimate but not, apparently, when z values are > >given. Perhaps packages splines or mclust will do this, although > >I haven't checked. More likely, the functions surf.ls(), surf.gls() > >from package spatial. > > > >Other users who are familiar with maps and geographic information > >systems (GIS) packages for R may have much better ideas for you > >than I know about. I've never had occasion to use any of this. > > > >- tom blackwell - u michigan medical school - ann arbor - > > > >On Fri, 19 Dec 2003, L Z wrote: > > > > > > > >>Question: > >> I have matrix (n x3) that represents discrete data. > >>Each row of matrix is 3-D point (x,y,z). I would like > >>to get contour map (z value) at two dimension > >>(x,y). How can I use related contour function to do > >>this job? > >>I am not sure if I clarify this question. For example, > >>we can get point (x,y) > >>at 2 dimension according to first two columns of > >>matrix. Then I want to connect > >>same value z=(x,y). Thanks! > >> zhang > >> > >>The data file looks like this: > >>X y z > >>4 0.33 0.99 > >>4 0.5 1.2 > >>5 0.66 1.2 > >>5 0.7 1.5 > >>6 2 1.2 > >>? > >> > >> > >> > > > >______________________________________________ > >[EMAIL PROTECTED] mailing list > >https://www.stat.math.ethz.ch/mailman/listinfo/r-help > > > > > > ______________________________________________ > [EMAIL PROTECTED] mailing list > https://www.stat.math.ethz.ch/mailman/listinfo/r-help > -- Roger Bivand Economic Geography Section, Department of Economics, Norwegian School of Economics and Business Administration, Breiviksveien 40, N-5045 Bergen, Norway. voice: +47 55 95 93 55; fax +47 55 95 93 93 e-mail: [EMAIL PROTECTED] ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help
