plotLines function

Plot a PolySet as Polylines

Plot a PolySet as polylines.

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

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 polylines to plot and their properties. par parameters passed as direct arguments supersede these data.
• lty: vector describing line types (cycled by PID).
• col: vector describing colours (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.

Details

This function plots a PolySet , where each unique (PID, SID) describes a polyline. It does not connect each polyline's last vertex to its first. Unlike plotMap, the function ignores the aspect ratio. It clips polys to xlim and ylim before plotting.

The 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 lty and col, please see par.

Returns

PolyData consisting of the PolyProps used to create the plot.

Note

To satisfy the aspect ratio, this plotting routine resizes the plot region. Consequently, par parameters such as plt, mai, and mar will change. When the function terminates, these changes persist to allow for additions to the plot.

Author(s)

Nicholas M. Boers, Staff Software Engineer

Jobber, Edmonton AB

Last modified Rd: 2013-04-10

See Also

addLines, calcLength, clipLines, closePolys, convLP, fixBound, fixPOS,

locatePolys, 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
  plotLines(polys, xlim=c(-.5,1.5), ylim=c(-.5,1.5))
  par(oldpar)
})