surfaces and digital terrain model
Renaud -
help("contour") gives a reference to filled.contour(), which might
do what you want by explicitly setting its "levels" argument to be
the single z value which corresponds to the water level. I have not
experimented to see whether filled.contour() will accept arguments
new=FALSE, add=TRUE which would allow it to add to an existing plot.
And, my information is relative to base R 1.6.1. More recent versions
of R may have other function names, such as "levelplot". Try the
help().
- tom blackwell - u michigan medical school - ann arbor -
On Thu, 29 May 2003, Renaud Lancelot wrote:
Dear all, I have computed a digital terrain model from a set of points (x, y, z) using the function interp() in package akima. I want to predict flooded surfaces given target values of z. I can display the flooded surfaces with contour() or image(), but I don't know how to get the polygons delimiting the surfaces. Did anyone write a function for this purpose ? Dr Renaud Lancelot, vétérinaire CIRAD, Département Elevage et Médecine Vétérinaire (CIRAD-Emvt) Programme Productions Animales http://www.cirad.fr/presentation/programmes/prod-ani.shtml ISRA-LNERV tel (221) 832 49 02 BP 2057 Dakar-Hann fax (221) 821 18 79 (CIRAD) Senegal e-mail renaud.lancelot at cirad.fr