inout: Test points for inclusion in a polygon

Description

Test points for inclusion in a polygon.

Usage

inout(pts,poly,bound=NULL,quiet=TRUE)

Value

A vector of logical values. TRUE means the point was inside the polygon, FALSE means the point was outside. Note that "inside" is an arbitrary concept for points "on" the polygon boundary.

Arguments

pts: A points data set
poly: A polygon data set
bound: If points fall exactly on polygon boundaries, the default NULL gives arbitrary assignments. If TRUE, then all points "on" boundaries are set as within the polygon, if FALSE, outside.
quiet: Do not report which points are on boundary for non-NULL bound

References

Rowlingson, B. and Diggle, P. 1993 Splancs: spatial point pattern analysis code in S-Plus. Computers and Geosciences, 19, 627-655; the original sources can be accessed at: https://www.maths.lancs.ac.uk/~rowlings/Splancs/. See also Bivand, R. and Gebhardt, A. 2000 Implementing functions for spatial statistical analysis using the R language. Journal of Geographical Systems, 2, 307-317.

Examples

Run this code

data(uganda)
suganda <- sbox(uganda$poly)
ruganda <- csr(suganda, 1000)
polymap(suganda)
polymap(uganda$poly, add=TRUE)
def <- inout(ruganda, uganda$poly, bound=NULL)
pointmap(as.points(ruganda[def,1], ruganda[def,2]), add=TRUE, col="black")
pointmap(as.points(ruganda[!def,1], ruganda[!def,2]), add=TRUE, col="red")
tru <- inout(ruganda, uganda$poly, bound=TRUE, quiet=FALSE)
which(tru & !def)
ds1 <- as.points(expand.grid(x=seq(-1.5,1.5,0.5), y=seq(-1.5,1.5,0.5)))
ds1.poly <- ds1[chull(ds1),]
ds2 <- as.points(rnorm(300),rnorm(300))
plot(ds2, type="n", asp=1)
polymap(ds1.poly, add=TRUE, border="lightblue", col="lightblue", lwd=1)
points(ds2[inout(ds2,ds1.poly),],  col="green",  pch=20)
points(ds2[!inout(ds2,ds1.poly),], col="orange", pch=20)
points(ds1[inout(ds1,ds1.poly),],  col="black",  pch=20)
points(ds1[!inout(ds1,ds1.poly),], col="red",    pch=20)
plot(ds2, type="n", asp=1)
polymap(ds1.poly, add=TRUE, border="lightblue", col="lightblue", lwd=1)
points(ds2[inout(ds2,ds1.poly,bound=TRUE),],  col="green",  pch=20)
points(ds2[!inout(ds2,ds1.poly,bound=TRUE),], col="orange", pch=20)
points(ds1[inout(ds1,ds1.poly,bound=TRUE),],  col="black",  pch=20)
points(ds1[!inout(ds1,ds1.poly,bound=TRUE),], col="red",    pch=20)
plot(ds2, type="n", asp=1)
polymap(ds1.poly, add=TRUE, border="lightblue", col="lightblue", lwd=1)
points(ds2[inout(ds2,ds1.poly,bound=FALSE),],  col="green",  pch=20)
points(ds2[!inout(ds2,ds1.poly,bound=FALSE),], col="orange", pch=20)
points(ds1[inout(ds1,ds1.poly,bound=FALSE),],  col="black",  pch=20)
points(ds1[!inout(ds1,ds1.poly,bound=FALSE),], col="red",    pch=20)