Voronoi hull model
Voronoi polygons for presence/absence data
## S4 method for signature 'matrix,matrix' voronoiHull(p, a, ext=NULL, dissolve=FALSE, crs=NA, ...) ## S4 method for signature 'data.frame,data.frame' voronoiHull(p, a, ext=NULL, dissolve=FALSE, crs=NA, ...) ## S4 method for signature 'SpatialPoints,SpatialPoints' voronoiHull(p, a, ext=NULL, dissolve=FALSE, ...)
p |
Presence points. Two column |
a |
Absence points. Must be of the same class as |
ext |
Extent to limit or expand the area of interest |
dissolve |
Boolean. Dissolve (aggregate) polygons? |
crs |
character or CRS object. PROJ.4 notation coordinate reference system |
... |
Additional arguments passed to |
A VoronoiHull object (inherits from DistModel-class)
This function is only correct when using a planar coordinate reference system (not longitude/latitude).
Robert J. Hijmans
r <- raster(system.file("external/rlogo.grd", package="raster"))
# presence points
p <- matrix(c(17, 42, 85, 70, 19, 53, 26, 84, 84, 46, 48, 85, 4, 95, 48, 54, 66, 74, 50, 48,
28, 73, 38, 56, 43, 29, 63, 22, 46, 45, 7, 60, 46, 34, 14, 51, 70, 31, 39, 26), ncol=2)
# absence points
a <- matrix(c(30, 23, 5, 5, 31, 33, 91, 63, 60, 88, 93, 97, 65, 68, 85, 97, 35, 32, 29, 55,
3, 8, 19, 71, 49, 36, 69, 41, 20, 28, 18, 9, 5, 9, 25, 71, 8, 32, 46, 60), ncol=2)
v <- voronoiHull(p, a)
x <- predict(r, v)
## Not run:
plot(x)
points(p, col='black', pch=20, cex=2)
points(a, col='red', pch=20, cex=2)
## End(Not run)Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.