usagePlot: Plot Usage

Description

This function displays variation in effort (usage) over detectors as a bubble plot (circles with radius scaled so that area is proportional to effort).

Usage

usagePlot(object, add = FALSE, occasion = NULL, col = "black", fill =
FALSE, scale = 2, metres = TRUE, rad = 5, ...)

Arguments

object

traps object with usage attribute

add

logical; if FALSE plot.traps is called to create a base plot

occasion

integer number of the occasion(s) for which effort is plotted, "ALL", or NULL

col

character or integer colour value

fill

logical; if TRUE the circle is filled with the line colour

scale

numeric value used to scale radius

metres

logical; if TRUE scale is a value in metres (see Details)

rad

numeric; radial displacement of symbol centre for each occasion from true detector location (metres)

...

other arguments passed to plot.traps

Value

No value is returned.

Details

By default (occasion = NULL) circles representing usage on each occasion are plotted around the detector location at distance rad, as in the petal plot of plot.capthist. Otherwise, the usage on a single specified occasion, or summed over occasions (length(occasion)>1, or occasion = "ALL"), is plotted as a circle centred at the detector location. The metres argument switches between two methods. If

metres
= TRUE

, the symbols function is used with inches = FALSE to plot circles with radius scaled in the units of object (i.e. metres; scale is then the radius in metres of the symbol for a detector with usage = 1.0). Otherwise, plotting uses points; this has the advantage of producing better filled circles, but a suitable value of scale must be found by trial and error. Package sp provides an alternative (see Examples).

Examples

Run this code

simgrid <- make.grid(nx = 10, ny = 10, detector = "proximity")
usage(simgrid) <- matrix(rep(1:10, 50), nrow = 100, ncol = 5)
usagePlot(simgrid, border = 20, scale = 1.5, fill = FALSE,
  metres = FALSE)

# It is hard to get the legend just right
# here is one attempt
legend (x = -50, y = 185, legend = c(1,2,5,10), pch = 1, pt.cex =
  c(1,2,5,10)^0.5 * 1.5, x.intersp = 3, y.intersp = 1.8, adj = 1,
  bty = "n", title = "Usage")

usagePlot(simgrid, occasion = NULL, border = 20, scale = 1.5, fill = FALSE,
  metres = FALSE)

# bubble plot in package 'sp'
library(sp)
simgrid$usage <- usage(simgrid)[,1]  ## occasion 1
class(simgrid) <- "data.frame"
coordinates(simgrid) <- c("x","y")
bubble(simgrid)

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