function to calculate sites weights

• wFUN_adw: angular distance weighting

• wFUN_idw: inverse distance weighting

• wFUN_mean: arithmetic average weighting

• wFUN_thiessen,wFUN_natural: natural neighbor interpolation (also known as thiessen interpolation)

wFUN_adw(dist, m = 4, cdd = 450, point, sites, ...)

wFUN_idw(dist, m = 2, ...)

wFUN_mean(dist, ...)

wFUN_thiessen(dist, ...)

wFUN_natural(dist, ...)

Arguments

dist

numeric vector, the distance between point and each sites, with the same length as sites.

m

distance weight (default 4)

cdd

the correlation decay distance (km) for adw and searching radius for others, default (450).

point

numeric vector c(lon, lat), the point needed to be interpolated

sites

matrix, cbind(lon, lat), coordinates of sites used to interpolate point

...

ignored