ptools (version 2.0.0)

vor_sp: Voronoi tesselation from input points

Description

Given an outline and feature points, calculates Voronoi areas

Usage

vor_sp(outline, feat)

Value

A SpatialPolygonsDataFrame object, including the dataframe for all the info in the orignal feat@data dataframe.

Arguments

outline

object that can be coerced to a spatstat window via as.owin (so SpatialPolygonDataFrame, SpatialPolygon, owin)

feat

A SpatialPointsDataFrame object (if duplicate X/Y coordinates will get errors)

Details

Outline should be a single polygon area. Uses spatstats dirichlet and window to compute the Voronoi tesselation. Will generate errors if feat has duplicate X/Y points. Useful to create areas for other functions, such as dcount_xy() or count_xy(). Common spatial unit of analysis used in crime research when using points (e.g. intersections and street midpoints).

References

Wheeler, A. P. (2018). The effect of 311 calls for service on crime in DC at microplaces. Crime & Delinquency, 64(14), 1882-1903.

Wheeler, A. P. (2019). Quantifying the local and spatial effects of alcohol outlets on crime. Crime & Delinquency, 65(6), 845-871.

Examples

# \donttest{
library(sp) # for sample/coordinates
data(nyc_bor)
nyc_buff <- buff_sp(nyc_bor,50000)
po <- sp::spsample(nyc_buff,20,'hexagonal')
po$id <- 1:dim(coordinates(po))[1] # turns into SpatialDataFrame
vo <- vor_sp(nyc_buff,po)
plot(vo)
plot(nyc_buff,border='RED',lwd=3, add=TRUE)
# }