# ipdwInterp: Inverse Distance Weighting with custom distances In jsta/ipdw: Spatial Interpolation by Inverse Path Distance Weighting

## Description

This function takes a rasterstack of pathdistances and generates surfaces by weighting parameter values by these distances

## Usage

  1 2 3 4 5 6 7 8 9 10 ipdwInterp( spdf, rstack, paramlist, overlapped = FALSE, yearmon = "default", removefile = TRUE, dist_power = 1, trim_rstack = FALSE ) 

## Arguments

 spdf SpatialPointsDataFrame object rstack RasterStack of path distances paramlist character. String representing parameter names overlapped logical. Default is FALSE, specify TRUE if some points lie on top of barriers yearmon character. String specifying the name of the spdf removefile logical. Remove files after processing? dist_power numeric. Distance decay power (p) trim_rstack logical. Trim the raster stack by the convex hull of spdf

## Details

Under the hood, this function evaluates:

V = \frac{∑\limits_{i=1}^n v_i \frac{1}{d_i^p}}{∑\limits_{i=1}^n \frac{1}{d_i^p}}

where d is the distance between prediction and measurement points, v_i is the measured parameter value, and p is a power parameter.

RasterLayer

Joseph Stachelek

## Examples

  1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 spdf <- data.frame(rnorm(2)) xy <- data.frame(x = c(4, 2), y = c(8, 4)) coordinates(spdf) <- xy m <- matrix(NA, 10, 10) costras <- raster(m, xmn = 0, xmx = ncol(m), ymn = 0, ymx = nrow(m)) # introduce spatial gradient costras[] <- runif(ncell(costras), min = 1, max = 10) for(i in 1:nrow(costras)){ costras[i,] <- costras[i,] + i costras[,i] <- costras[,i] + i } rstack <- pathdistGen(spdf, costras, 100, progressbar = FALSE) final.raster <- ipdwInterp(spdf, rstack, paramlist = c("rnorm.2."), overlapped = TRUE) plot(final.raster) plot(spdf, add = TRUE) 

jsta/ipdw documentation built on July 27, 2020, 11:41 a.m.