Select parts of polygons not shared between two GVectors

The xor() function selects the area that does not overlap between two "polygon" GVectors. You can also use the / operator, as in vect 1 / vect2.

Usage

# S4 method for class 'GVector,GVector'
xor(x, y)

Arguments

x, y

GVectors.

Value

A GVector.

See also

c(), aggregate(), crop(), intersect(), union(), erase()

Examples

if (grassStarted()) {

# Setup
library(sf)

# Polygon of coastal Madagascar and Dypsis specimens
madCoast4 <- fastData("madCoast4") # polygons
madDypsis <- fastData("madDypsis") # points

# Convert vectors:
coast4 <- fast(madCoast4)
dypsis <- fast(madDypsis)

# Create another polygons vector from a convex hull around Dypsis points
hull <- convHull(dypsis)

### union()
###########

unioned <- union(coast4, hull)
plot(unioned)

plus <- coast4 + hull # same as union()

### intersect
#############

inter <- intersect(coast4, hull)
plot(coast4)
plot(hull, border = "red", add = TRUE)
plot(inter, border = "blue", add = TRUE)

### xor
#######

xr <- xor(coast4, hull)
plot(coast4)
plot(xr, border = "blue", add = TRUE)

### erase
#########

erased <- erase(coast4, hull)
plot(coast4)
plot(erased, border = "blue", add = TRUE)

minus <- coast4 - hull # same as erase()

}