PBSmapping (version 2.73.2)

plotPolys: Plot a PolySet as Polygons

Description

Plot a PolySet as polygons.

Usage

plotPolys (polys, xlim = NULL, ylim = NULL, projection = FALSE,
           plt = c(0.11, 0.98, 0.12, 0.88), polyProps = NULL,
           border = NULL, lty = NULL, col = NULL, colHoles = NULL,
           density = NA, angle = NULL, bg = 0, axes = TRUE,
           tckLab = TRUE, tck = 0.014, tckMinor = 0.5 * tck, ...)

Value

PolyData consisting of the PolyProps used to create the plot.

Arguments

polys

PolySet to plot (required).

xlim

range of X-coordinates.

ylim

range of Y-coordinates.

projection

desired projection when PolySet lacks a projection attribute; one of "LL", "UTM", or a numeric value. If Boolean, specifies whether to check polys for a projection attribute.

plt

four element numeric vector (x1, x2, y1, y2) giving the coordinates of the plot region measured as a fraction of the figure region. Set to NULL if mai in par is desired.

polyProps

PolyData specifying which polygons to plot and their properties. par parameters passed as direct arguments supersede these data.

border

vector describing edge colours (cycled by PID).

lty

vector describing line types (cycled by PID).

col

vector describing fill colours (cycled by PID).

colHoles

vector describing hole colours (cycled by PID). The default, NULL, should be used in most cases as it renders holes transparent. colHoles is designed solely to eliminate retrace lines when images are converted to PDF format. If colHoles is specified, underlying information (i.e., previously plotted shapes) will be obliterated. If NA is specified, only outer polygons are drawn, consequently filling holes.

density

vector describing shading line densities (lines per inch, cycled by PID).

angle

vector describing shading line angles (degrees, cycled by PID).

bg

background colour of the plot.

axes

Boolean value; if TRUE, plot axes.

tckLab

Boolean vector (length 1 or 2); if TRUE, label the major tick marks. If given a two-element vector, the first element describes the tick marks on the x-axis and the second element describes those on the y-axis.

tck

numeric vector (length 1 or 2) describing the length of tick marks as a fraction of the smallest dimension. If tckLab = TRUE, these tick marks will be automatically labelled. If given a two-element vector, the first element describes the tick marks on the x-axis and the second element describes those on the y-axis.

tckMinor

numeric vector (length 1 or 2) describing the length of tick marks as a fraction of the smallest dimension. These tick marks can not be automatically labelled. If given a two-element vector, the first element describes the tick marks on the x-axis and the second element describes those on the y-axis.

...

additional par parameters, or the arguments main, sub, xlab, or ylab for the title function.

Author

Nicholas M. Boers, Associate Professor -- Computer Science
MacEwan University, Edmonton AB
Last modified Rd: 2013-04-10

Details

This function plots a PolySet, where each unique (PID, SID) describes a polygon. It connects each polygon's last vertex to its first. The function supports both borders (border, lty) and fills (col, density, angle). When supplied with the appropriate arguments, it can draw only borders or only fills. Unlike plotMap, it ignores the aspect ratio. It clips polys to xlim and ylim before plotting.

This function creates a blank plot when polys equals NULL. In this case, the user must supply both xlim and ylim arguments. Alternatively, it accepts the argument type = "n" as part of ..., which is equivalent to specifying polys = NULL, but requires a PolySet. In both cases, the function's behaviour changes slightly. To resemble the plot function, it plots the border, labels, and other parts according to par parameters such as col.

For additional help on the arguments border, lty, col, density, and angle, please see polygon and par.

See Also

addLabels, addPolys, addStipples, clipPolys, closePolys, fixBound, fixPOS, locatePolys, plotLines, plotMap, plotPoints, thinPolys, thickenPolys.

Examples

local(envir=.PBSmapEnv,expr={
  oldpar = par(no.readonly=TRUE)
  #--- create a PolySet to plot
  polys <- data.frame(PID=rep(1,4),POS=1:4,X=c(0,1,1,0),Y=c(0,0,1,1))
  #--- plot the PolySet
  plotPolys(polys, xlim=c(-.5,1.5), ylim=c(-.5,1.5), density=0)
  par(oldpar)
})