Plot methods for spatial data with attributes

Description

Lattice (trellis) plot methods for spatial data with attributes

Usage

spplot(obj, ...)
spplot.grid(obj, zcol = names(obj), ..., names.attr, 
        scales = list(draw = FALSE), xlab = NULL, ylab = NULL, aspect = mapasp(obj,xlim,ylim), 
        panel = panel.gridplot, sp.layout = NULL, formula, xlim = bbox(obj)[1, ], 
        ylim = bbox(obj)[2, ], checkEmptyRC = TRUE)
spplot.polygons(obj, zcol = names(obj), ..., names.attr, 
        scales = list(draw = FALSE), xlab = NULL, ylab = NULL, aspect = mapasp(obj,xlim,ylim), 
        panel = panel.polygonsplot, sp.layout = NULL, formula, xlim = bbox(obj)[1, ], 
        ylim = bbox(obj)[2, ])
spplot.points(obj, zcol = names(obj), ..., names.attr, 
        scales = list(draw = FALSE), xlab = NULL, ylab = NULL, aspect = mapasp(obj,xlim,ylim), 
        panel = panel.pointsplot, sp.layout = NULL, identify = FALSE, formula, 
        xlim = bbexpand(bbox(obj)[1, ], 0.04), ylim = bbexpand(bbox(obj)[2, ], 0.04))
mapLegendGrob(obj, widths = unit(1, "cm"), heights = unit(1, "cm"),
        fill = "black", just = "right")
sp.theme(set = FALSE, regions = list(col = bpy.colors(100)), ...)
layout.north.arrow(type = 1)
layout.scale.bar(height = 0.05)
spplot.locator(n = 512, type = "n", ...)

Arguments

Value

spplot returns a lattice plot of class "trellis", if you fail to "see" it, explicitly call print(spplot(...)). If identify is TRUE, the plot is plotted and the return value is a vector with row names of the selected points.
spplot.locator returns a matrix with identified point locations; use trellis.focus first to focus on a given panel.

Methods

obj = "SpatialPixelsDataFrame"

see spplot

obj = "SpatialGridDataFrame"

see spplot

obj = "SpatialPolygonsDataFrame"

see spplot

obj = "SpatialLinesDataFrame"

see spplot

obj = "SpatialPointsDataFrame"

see spplot

Note

Missing values in the attributes are (currently) not allowed.

spplot.grid, spplot.polygons and spplot.points are S4 methods for spplot; see spplot-methods.

Useful arguments that can be passed as ... are:

layout

for the layout of panels

col.regions

to specify fill colours; in case the variable to be plotted is a factor, this vector should have length equal to the number of factor levels; when plotting points it may also have length one, using symbol type to distinguish classes

pretty

for colour breaks at pretty numbers

at

to specify at which values colours change

as.table

to start drawing panels upper-left instead of lower-left

page

to add marks to each plotted page

for useful values see the appropriate documentation of xyplot and levelplot.

If obj is of SpatialPointsDataFrame, the following options are useful to pass:

key.space

character: "bottom", "right", "left" or "right" to denote key location, or list: see argument key in the help for xyplot what the options are

legendEntries

character; array with key legend (text) entries; suitable defaults obtained from data

cuts

number of cuts or the actual cuts to use

do.log

logical; if TRUE use log-linear scale to divide range in equal cuts, else use a linear scale if cuts is only number of cuts

pch

integer; plotting character to use; defaults to 16 if fill is TRUE, else 1

cex

numeric; character expansion, proportional to default value of 1

fill

logical; use filled circles?

layout.north.arrow and layout.scale.bar can be used to set a north arrow or scale bar.

The sp.layout argument is either a single layout item, or a list with a layout items. A layout item is a list with its first argument the name of the layout function to be called: sp.points for SpatialPoints, sp.polygons for SpatialPolygons object, sp.lines for a SpatialLines object, and sp.text for text to place. The second argument contains the object (or text) to be plotted; remaining arguments are passed to the corresponding panel.* functions.

A special layout list item is which (integer), to control to which panel a layout item should be added. If which is present in the main, top-level list it applies for all layout items; in sub-lists with layout items it denotes the (set of) panels in which the layout item should be drawn. Without a which item, layout items are drawn in each panel.

The order of items in sp.layout matters; objects are drawn in the order they appear. Plot order and prevalence of sp.layout items: for points and lines, sp.layout items are drawn before the points (to allow for grids and polygons); for grids and polygons sp.layout is drawn afterwards (so the item will not be overdrawn by the grid and/or polygon). Although a matter of taste, transparency may help when combining things.

sp.theme returns a lattice theme; use trellis.par.set(sp.theme()) after a device is opened or changed to make this work. Currently, this only sets the colors to bpy.colors.

If the attributes to be plotted are of type factor, spplot tries to create a legend that reflects this. In this case, the color ramp passed needs to be of the same length as the number of factor levels. The factor levels are derived from the first map; subsequent factors with different factor levels result in an error.

Author(s)

Edzer Pebesma, edzer.pebesma@uni-muenster.de

References

http://r-spatial.sourceforge.net/

See Also

xyplot, levelplot

Examples

library(lattice)
trellis.par.set(sp.theme()) # sets bpy.colors() ramp
data(meuse)
coordinates(meuse) <- ~x+y
l2 = list("SpatialPolygonsRescale", layout.north.arrow(), offset = c(181300,329800), 
        scale = 400)
l3 = list("SpatialPolygonsRescale", layout.scale.bar(), offset = c(180500,329800), 
        scale = 500, fill=c("transparent","black"))
l4 = list("sp.text", c(180500,329900), "0")
l5 = list("sp.text", c(181000,329900), "500 m")

spplot(meuse, c("ffreq"), sp.layout=list(l2,l3,l4,l5), col.regions= "black", 
        pch=c(1,2,3), key.space=list(x=0.1,y=.95,corner=c(0,1)))
spplot(meuse, c("zinc", "lead"), sp.layout=list(l2,l3,l4,l5, which = 2),
        key.space=list(x=0.1,y=.95,corner=c(0,1)))
# plotting factors:
meuse$f = factor(sample(letters[6:10], 155, replace=TRUE),levels=letters[1:10])
meuse$g = factor(sample(letters[1:5], 155, replace=TRUE),levels=letters[1:10])
spplot(meuse, c("f","g"), col.regions=bpy.colors(10))

if (require(RColorBrewer)) {
        spplot(meuse, c("ffreq"), sp.layout=list(l2,l3,l4,l5),
                col.regions=brewer.pal(3, "Set1"))
}

data(meuse.grid)
gridded(meuse.grid)=~x+y
meuse.grid$g = factor(sample(letters[1:5], 3103, replace=TRUE),levels=letters[1:10])
meuse.grid$f = factor(sample(letters[6:10], 3103, replace=TRUE),levels=letters[1:10])
spplot(meuse.grid, c("f","g"))
spplot(meuse.grid, c("f","g"), col.regions=bpy.colors(10))