smoothingMatrix: Generates the smoothing matrix for the partitions and...

In localEM: Nonparametric Modelling of Spatial Risk for Areal Disease Data

Description

The smoothingMatrix function computes the entries of the smoothing matrix for the local-EM algorithm for the input bandwidths based on the partitions created by rasterizing the spatial polygons of case and population data, and their smoothed offsets created by applying the kernel smoothing function with input bandwidths.

Usage

smoothingMatrix(rasterObjects, ncores = 1, path = getwd(),
  filename = "lemSmoothMat.grd", verbose = FALSE)

Arguments

rasterObjects	Raster stacks for partitions and smoothed offsets
ncores	Number of cores/threads for parallel processing
path	Folder to store raster data
filename	Filename (must have .grd extension) of the entries of smoothing matrix
verbose	Verbose output

Details

After using the smoothingMatrix function, the smoothing matrix is an array containing the integrated kernel smoothing entries of the partitions divided by the integrated kernel smoothing entries of the study region for each specified bandwidth.

Value

The smoothingMatrix function returns a list containing an array of smoothing matrix entries, and the input rasters of partitions and smoothed offsets.

Examples

## Not run:  
# case and population data
data('kentuckyCounty')
data('kentuckyTract')

# parameters
ncores = 2
cellsCoarse = 8
cellsFine = 100
bw = c(10, 15, 17.5, 20) * 1000
path = 'example'

# rasters of case and population data
lemRaster = rasterPartitionSingle(polyCoarse = kentuckyCounty, 
							polyFine = kentuckyTract, 
							cellsCoarse = cellsCoarse, 
							cellsFine = cellsFine, 
							bw = bw, 
							ncores = ncores, 
							path = path, 
							idFile = 'lemId.grd', 
							offsetFile = 'lemOffsets.grd', 
							verbose = TRUE)

# smoothing matrix
lemSmoothMat = smoothingMatrixSingle(rasterObjects = lemRaster, 
								ncores = ncores, 
								path = path, 
								filename = 'lemSmoothMat.grd', 
								verbose = TRUE)

## End(Not run)

localEM documentation built on May 3, 2019, 1:24 p.m.