panel.voronoi {latticeExtra} | R Documentation |

These panel functions for `levelplot`

can represent irregular (x, y) points with a color covariate.
`panel.levelplot.points`

simply draws color-coded points.
`panel.voronoi`

uses the deldir package to
calculate the spatial extension of a set of points in 2 dimensions.
This is known variously as a Voronoi mosaic, a Dirichlet tesselation,
or Thiessen polygons.

panel.voronoi(x, y, z, subscripts = TRUE, at = pretty(z), points = TRUE, border = "transparent", na.rm = FALSE, win.expand = 0.07, use.tripack = FALSE, ..., col.regions = regions$col, alpha.regions = regions$alpha) panel.levelplot.points(x, y, z, subscripts = TRUE, at = pretty(z), shrink, labels, label.style, contour, region, pch = 21, col.symbol = "#00000044", ..., col.regions = regions$col, fill = NULL)

`x, y, z` |
an irregular set of points at locations (x, y) with value z. |

`subscripts` |
integer vector indicating what subset of x, y and z
to draw. Typically passed by |

`at, col.regions, alpha.regions` |
color scale definition;
see |

`points` |
whether to draw the (x, y) points. |

`border` |
color for polygon borders. |

`na.rm` |
if |

`win.expand` |
defines the rectangular window bounding the
polygons. This is a factor by which
to expand the range of the data. Set to 0 to limit drawing at the
furthest data point locations. Ignored if |

`use.tripack` |
if |

`...` |
further arguments are
passed to |

`pch, col.symbol` |
symbol and border color for points. A filled symbol should be used, i.e. in the range 21-25. |

`shrink, labels, label.style, contour, region, fill` |
ignored. |

The tripack package implementation is faster than deldir but not under a
fully free licence. Also, the deldir package allows polygons to
be clipped to a rectangular window (the `win.expand`

argument).

Felix Andrews felix@nfrac.org

`tileplot`

,
`panel.levelplot`

,
`deldir`

## a variant of Figure 5.6 from Sarkar (2008) ## http://lmdvr.r-forge.r-project.org/figures/figures.html?chapter=05;figure=05_06 depth.ord <- rev(order(quakes$depth)) quakes$Magnitude <- equal.count(quakes$mag, 4) quakes.ordered <- quakes[depth.ord, ] levelplot(depth ~ long + lat | Magnitude, data = quakes.ordered, panel = panel.levelplot.points, type = c("p", "g"), aspect = "iso", prepanel = prepanel.default.xyplot) ## a levelplot with jittered cells xyz <- expand.grid(x = 0:9, y = 0:9) xyz[] <- jitter(as.matrix(xyz)) xyz$z <- with(xyz, sqrt((x - 5)^2 + (y - 5)^2)) levelplot(z ~ x * y, xyz, panel = panel.voronoi, points = FALSE) ## hexagonal cells xyz$y <- xyz$y + c(0, 0.5) levelplot(z ~ x * y, xyz, panel = panel.voronoi, points = FALSE)

[Package *latticeExtra* version 0.6-25 Index]