spplot {sp}R Documentation

Lattice (trellis) plots for spatial data

Description

plots for points, grids, polygons

Usage

spplot(obj, ...)
spplot.grid(obj, zcol = names(obj), ..., names.attr, 
        scales = list(draw = FALSE), xlab = "", ylab = "", aspect = mapasp(obj), 
        panel = panel.gridplot, sp.layout = NULL, formula)
spplot.rings(obj, zcol = names(obj), ..., names.attr, 
        scales = list(draw = FALSE), xlab = "", ylab = "", aspect = mapasp(obj), 
        panel = panel.ringsplot, sp.layout = NULL, formula)
spplot.points(obj, zcol = names(obj), ..., names.attr, 
        scales = list(draw = FALSE), xlab = "", ylab = "", aspect = mapasp(obj), 
        panel = panel.pointsplot, sp.layout = NULL, identify = FALSE, formula)
mapLegendGrob(obj, widths = unit(1, "cm"), heights = unit(1, "cm"),
        fill = "black", just = "right")
sp.theme()
layout.north.arrow()
layout.scale.bar(height = 0.05)

Arguments

obj object of class extending Spatial-class
zcol character; attribute name(s) or column number(s) in attribute table
names.attr names to use in panel, if different from zcol names
scales scales argument to be passed to Lattice plots; use list(draw = TRUE) to draw axes scales; see xyplot for full options
... other arguments passed to levelplot (grids, polygons) or xyplot (points)
xlab label for x-axis
ylab label for y-axis
aspect aspect ratio for spatial axes; defaults to "iso" (one unit on the x-axis equals one unit on the y-axis) but may be set to more suitable values if the data are e.g. if coordinates are latitude/longitude
panel depending on the class of obj, panel.ringsplot (for rings or lines), panel.gridplot (grids) or panel.pointsplot (points) is used; for further control custom panel functions can be supplied that call one of these panel functions, but do read how the argument sp.layout may help
sp.layout NULL or list; see notes below
identify if not FALSE, identify plotted objects (currently only working for points plots). Labels for identification are the row.names of the attribute table row.names(as.data.frame(obj)). If TRUE, identify on panel (1,1); for identifying on panel i,j, pass the value c(i,j)
formula optional; may be useful to plot a transformed value. Defaults to z~x+y for single and z~x+y|name for multiple attributes; use e.g. exp(x)~x+y|name to plot the exponent of the z-variable
widths width of grob
heights heights of grob
fill fill color of grob
just grob placement justification
height height of scale bar; width is 1.0

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.

Note

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

spplot.grid, spplot.rings 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
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.polygon 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.

Author(s)

Edzer J. Pebesma, e.pebesma@geo.uu.nl

References

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

See Also

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)))

if (require(RColorBrewer)) {
        spplot(meuse, c("ffreq"), sp.layout=list(l2,l3,l4,l5),
                col.regions=brewer.pal(3, "Set1"))
}
[Package sp version 0.7-12 Index]