spplot {sp}

Plot methods for spatial data with attributes

Package:

Version:

0.9-79

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

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.polygonsplot (for polygons 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
xlim: numeric; x-axis limits
ylim: numeric; y-axis limits
widths: width of grob
heights: heights of grob
fill: fill color of grob
just: grob placement justification
set: logical; if TRUE, trellis.par.set is called, else a list is returned that can be passed to trellis.par.set()
regions: color ramp for the theme
height: height of scale bar; width is 1.0
n: see locator
type: see locator
checkEmptyRC: logical; if TRUE, a check is done to see if empty rows or columns are present, and need to be taken care of. Setting to FALSE may improve speed.

Values

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

References

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

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, for objects of class SpatialPointsDataFrame only, 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.

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), 
&nbsp;&nbsp;&nbsp;&nbsp;scale = 400)
l3 = list("SpatialPolygonsRescale", layout.scale.bar(), offset = c(180500,329800), 
&nbsp;&nbsp;&nbsp;&nbsp;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", 
&nbsp;&nbsp;&nbsp;&nbsp;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),
&nbsp;&nbsp;&nbsp;&nbsp;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)) {
&nbsp;&nbsp;&nbsp;&nbsp;spplot(meuse, c("ffreq"), sp.layout=list(l2,l3,l4,l5),
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;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))

Author(s)

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

Documentation reproduced from package sp, version 0.9-79. License: GPL (>= 2)