pycno (version 1.4)

pycno-package: Pycnophylactic Interpolation

Description

Given a SpatialPolygonsDataFrame and a set of populations for each polygon, compute a population density estimate based on Tobler's pycnophylactic interpolation algorithm. The result is a SpatialGridDataFrame.

Author

Chris Brunsdon

Maintainer: Francesca Bitonti

Details

Package:	pycno
Type:	Package
Version:	1.4
Date:	2023-09-28
License:	GPL (>=2)
LazyLoad:	yes

For use in conjunction with the sp package, computes pycnophylactic surfaces given a SpatialPolygonsDataFrame and a population for each poplygon. A pycnophylactic surface is smooth, but populations allocated to each pixel sum up to the initial polygon counts, when summed over the polygons contained in each pixel.

References

Tobler, W.R. (1979) Smooth Pycnophylactic Interpolation for Geographical Regions. Journal of the American Statistical Association, v74(367) pp. 519-530.

Examples

library(sp)
# Read in data for North Carolina as a SpatialPolygonsDataFrame
#nc.sids <- readShapeSpatial(system.file("shapes/sids.shp", package="maptools")[1], 
#  IDvar="FIPSNO", proj4string=CRS("+proj=longlat +ellps=clrk66"))

nc.sids <- as(sf::st_read(system.file("shape/nc.shp", package="sf")), "Spatial")
row.names(nc.sids) <- as.character(nc.sids$FIPSNO)

# Compute the pycnophylactic surface for 1974 births as a SpatialGridDataFrame
# Note probably shouldn't really base grid cells on Lat/Long coordinates
# This example just serves to illustrate the use of the function
births74 <- pycno(nc.sids,nc.sids$BIR74,0.05, converge=1)

# Draw it
image(births74)

# Overlay North Carolina county boundaries for reference
plot(nc.sids,add=TRUE)