selectObsWindow.stppp: selectObsWindow.stppp function
Description
This function computes an appropriate observation window on
which to perform prediction. Since the FFT grid must have
dimension 2^M by 2^N for some M and N, the window
xyt$window, is extended to allow this to be fit in
for a given cell width.Usage
## S3 method for class 'stppp':
selectObsWindow(xyt, cellwidth, ...)
Arguments
xyt
an object of class stppp
cellwidth
size of the grid spacing in chosen units
(equivalent to the cell width argument in
lgcpPredict) Value
- a resized stppp object together with grid sizes M and N
ready for FFT, together with the FFT grid locations, can be
useful for estimating lambda(s)
Details
!!NOTE!! that this function also returns the grid ($xvals
and $yvals) on which the FFT (and hence MALA) will be
performed. It is useful to define spatialAtRiskobjects on
this grid to prevent loss of information from the bilinear
interpolation that takes place as part of the fitting
algorithm.