This function is an alternative to density.ppp
and density.lpp. It
computes an estimate of the intensity function of a point pattern
dataset. The result is a pixel image giving the estimated intensity.
If method="voronoi" the data are passed to the function
densityVoronoi which estimates the intensity using
the Voronoi-Dirichlet tessellation.
If method="kernel" the data are passed to the function
densityAdaptiveKernel.ppp which estimates the intensity
using a variable-bandwidth kernel estimator. (This is not yet supported
when X has class "lpp".)
If method="nearest" the data are passed to the function
nndensity.ppp which estimates the intensity using the
distance to the k-th nearest data point. (This is not yet supported
when X has class "lpp".)