Plot probability of detection as a directional range footprint

Renders p(det) as a function of range and azimuth around the recorder, in Cartesian coordinates – the direct ggplot2 equivalent of Brian's MATLAB plotPDetRadials.m, which builds the same picture via pcolor(x = r*cos(theta), y = r*sin(theta), z). Uses the same default ggplot2 colour scale and theme as plotSpatialDetections.

Usage

plotPDetRadials(
  pDetResults,
  maxRange = NULL,
  method = c("polygon", "raster"),
  arcPoints = NULL,
  rasterRes = 400
)

Arguments

pDetResults

Either the full list returned by pDetInArea (in which case $allDetFunctions is used), or that data.frame directly – range_m in the first column, one column per transect named tl<angle> (matching simTLradials_20logR's convention) giving p(det) at every range along that transect. angle is a compass bearing, 0 = true north, increasing clockwise.

maxRange

Optional upper limit (m) for the range axis. Default NULL uses the full range present in the data.

method

"polygon" (default) draws each cell as an exact annular-sector patch – no interpolation, the direct equivalent of MATLAB's pcolor. "raster" nearest-neighbour-resamples onto a fine square grid instead, which can look smoother at very coarse azimuthal resolution but is drawing resampled, not sampled, pixels.

arcPoints

Only used when method = "polygon". Number of vertices used for each cell's inner/outer arc. NULL (default) auto-selects based on the number of azimuths present – see pdetPolygonGrid. Set explicitly to override, e.g. to force straight chords (arcPoints = 2) even at coarse azimuthal resolution.

rasterRes

Only used when method = "raster". Number of pixels along each axis of the output grid. Default 400.

Value

A ggplot object.

Details

Assumes a constant range step and constant azimuth step (true of simTLradials_20logR's output and of pDetInArea's own output.resolution.m spacing).