construct inverse distance weight

Function for constructing inverse distance weight.

Usage

inverse_distance_swm(sfj, power = 1, bandwidth = NULL)

Arguments

sfj

Vector object that can be converted to sf by sf::st_as_sf().

power

(optional) Default is 1. Set to 2 for gravity weights.

bandwidth

(optional) When the distance is bigger than bandwidth, the corresponding part of the weight matrix is set to 0. Default is NULL, which means not use the bandwidth.

Value

A inverse distance weight matrices with class of matrix.

Details

The inverse distance weight formula is \(w_{ij} = 1 / d_{ij}^\alpha\)

Examples

library(sf)
#> Linking to GEOS 3.12.1, GDAL 3.8.4, PROJ 9.4.0; sf_use_s2() is TRUE
pts = read_sf(system.file('extdata/pts.gpkg',package = 'sdsfun'))
wt = inverse_distance_swm(pts)
wt[1:5,1:5]
#>              1            2            3            4            5
#> 1 0.000000e+00 5.813118e-05 1.654238e-04 3.818149e-05 7.868869e-05
#> 2 5.813118e-05 0.000000e+00 7.576789e-05 2.988167e-05 3.913838e-05
#> 3 1.654238e-04 7.576789e-05 0.000000e+00 4.239359e-05 7.877952e-05
#> 4 3.818149e-05 2.988167e-05 4.239359e-05 0.000000e+00 6.845458e-05
#> 5 7.868869e-05 3.913838e-05 7.877952e-05 6.845458e-05 0.000000e+00