This function is called by functions PlotTraj and PlotTrajFreq
just to add map's background.
Usage
PlotBgMap(traj, ...)
Arguments
traj
SpatialLines or SpatialLinesDataFrame object calculated by functions Df2SpLines or
Df2SpLinesDf. PlotBgMap uses this object (traj) to get the bounding box values for drawing the map.
...
Further arguments to the generic plot function.
Details
This function uses the preloaded data set canada.map.