The R package ipdw
provides the functionality to perform interpolation of georeferenced
point data using inverse path distance weighting. Interpolation is
accomplished in two steps. First, path distances are calculated from
each georeferenced (measurement) point to each prediction point. Path
distances, which honor barriers in the landscape, are calculated based
on cell-to-cell movement through an underlying Raster object that
represents movement cost. These path distances are subsequently used as
interpolation weights. The two-step routine follows the order of
operations described in Suominen et al. (2010) substituting the ESRI
path distance algorithm with the gdistance wrapped version of the
igraph adjacency algorithm.
The ipdw package was developed with coastal marine applications in mind where path distances (as the fish swims) rather than Euclidean (as the crow flies) distances more accurately represent spatial connectivity. Interpolation of sparse grids in coastal areas otherwise end up bleeding through land areas.
install.packages("ipdw")install.packages("devtools") # package devtools needed
devtools::install_github("jsta/ipdw")see vignette
J. Stachelek and Christopher J. Madden (2015). Application of Inverse Path Distance weighting for high density spatial mapping of coastal water quality patterns. International Journal of Geographical Information Science preprint | journal
Tapio Suominen, Harri Tolvanen, and Risto Kalliola (2010). Surface layer salinity gradients and flow patterns in the archipelago coast of SW Finland, northern Baltic Sea. Marine Environmental Research journal