
Poisson Models 349
gridcentres, stratrand, and spokes. It is also possible to ge nerate dummy points according
to a quasirandom scheme, using the functions Halton and Hammersley. Quasirandom patterns fill
the spac e uniformly but without any obvious regularities: they may be prefer able to regular grids.
quadscheme(X, ..., method="d") sp ecify Dirichlet weights
quadscheme(X, ..., ntile=8) 8 ×8 arr ay o f counting tiles
Table 9.7. Typical options for co ntrolling the quadrature weights.
The quadrature weights are determined by further arguments to quadscheme. If method =
"grid" (the default) the window is divided into an ntile[1] by ntile[2] grid of