areapl {splancs}

Calculate area of polygon

Description

Calculate area of polygon. If the polygon is self-intersecting, the area will not be correct.

Usage

areapl(poly)

Arguments

poly

a polygon data set

Value

The area of the polygon is returned

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

x <- c(1,0,0,1,1,1,1,3,3,1)
y <- c(0,0,1,1,0,0,-1,-1,0,0)
m <- cbind(x, y)
plot(m, type="b")
areapl(m)
areapl(m[1:5,])
areapl(m[6:10,])