plotpolyf function

Plot Polygonal Domain on Image of Bivariate Function

Produces a combined plot of a polygonal domain and an image of a bivariate function, using either lattice::levelplot

or image.

plotpolyf(polyregion, f, ..., npixel = 100, cuts = 15,
  col = rev(heat.colors(cuts + 1)), lwd = 3, xlim = NULL, ylim = NULL,
  use.lattice = TRUE, print.args = list())

Arguments

• polyregion: a polygonal domain. The following classes are supported: "owin" from package spatstat.geom, "gpc.poly" from gpclib, "SpatialPolygons", "Polygons", and "Polygon" from package sp, as well as "(MULTI)POLYGON" from package sf. (For these classes, polyCub knows how to get an xylist.)

• f: a two-dimensional real-valued function. As its first argument it must take a coordinate matrix, i.e., a numeric matrix with two columns, and it must return a numeric vector of length the number of coordinates.

• ...: further arguments for f.

• npixel: numeric vector of length 1 or 2 setting the number of pixels in each dimension.

• cuts: number of cut points in the $z$ dimension. The range of function values will be divided into cuts+1 levels.

• col: color vector used for the function levels.

• lwd: line width of the polygon edges.

• xlim, ylim: numeric vectors of length 2 setting the axis limits. NULL means using the bounding box of polyregion.

• use.lattice: logical indicating if lattice graphics (levelplot) should be used.

• print.args: a list of arguments passed to print.trellis

  for plotting the produced "trellis" object (given use.lattice = TRUE). The latter will be returned without explicit printing if print.args is not a list.

Examples

### a polygonal domain (a simplified version of spatstat.data::letterR$bdry)
letterR <- list(
    list(x = c(2.7, 3, 3.3, 3.9, 3.7, 3.4, 3.8, 3.7, 3.4, 2, 2, 2.7),
         y = c(1.7, 1.6, 0.7, 0.7, 1.3, 1.8, 2.2, 2.9, 3.3, 3.3, 0.7, 0.7)),
    list(x = c(2.6, 2.6, 3, 3.2, 3),
         y = c(2.2, 2.7, 2.7, 2.5, 2.2))
)

### f: isotropic exponential decay
fr <- function(r, rate = 1) dexp(r, rate = rate)
fcenter <- c(2,3)
f <- function (s, rate = 1) fr(sqrt(rowSums(t(t(s)-fcenter)^2)), rate = rate)

### plot
plotpolyf(letterR, f, use.lattice = FALSE)
plotpolyf(letterR, f, use.lattice = TRUE)

Author(s)

Sebastian Meyer