dirichlet.weights(X, window=NULL, exact=TRUE)
TRUE, compute exact areas using the package
FALSE, compute approximate areas using a pixel raster.
quad.objectfor an explanation of quadrature weights and quadrature schemes.
The weights are computed using the Dirichlet tessellation.
X and (optionally)
window are converted into a
point pattern object. Then the Dirichlet tessellation of the points
X is computed.
The weight attached to a point of
X is the area of
its Dirichlet tile (inside the window
exact=TRUE the Dirichlet tessellation is computed exactly
by the Lee-Schachter algorithm using the package
Otherwise a pixel raster approximation is constructed and the areas
are approximations to the true weights. In all cases the sum of the
weights is equal to the area of the window.
library(spatstat) Q <- quadscheme(runifpoispp(10)) X <- as.ppp(Q) # data and dummy points together w <- dirichlet.weights(X, exact=FALSE)