inpolygon
From pracma v1.9.9
by HwB
Polygon Region
Points inside polygon region.
 Keywords
 geom
Usage
inpolygon(x, y, xp, yp, boundary = FALSE)
Arguments
 x, y
 x, ycoordinates of points to be tested for being inside the polygon region.
 xp, yp
 coordinates of the vertices specifying the polygon.
 boundary
 Logical; does the boundary belong to the interior.
Details
For a polygon defined by points (xp, yp)
, determine if the
points (x, y)
are inside or outside the polygon. The boundary
can be included or excluded (default) for the interior.
Value

Logical vector, the same length as
x
.
Note
Special care taken for points on the boundary.
References
Hormann, K., and A. Agathos (2001). The Point in Polygon Problem for Arbitrary Polygons. Computational Geometry, Vol. 20, No. 3, pp. 131144.
See Also
Examples
xp < c(0.5, 0.75, 0.75, 0.5, 0.5)
yp < c(0.5, 0.5, 0.75, 0.75, 0.5)
x < c(0.6, 0.75, 0.6, 0.5)
y < c(0.5, 0.6, 0.75, 0.6)
inpolygon(x, y, xp, yp, boundary = FALSE) # FALSE
inpolygon(x, y, xp, yp, boundary = TRUE) # TRUE
## Not run:
# pg < matrix(c(0.15, 0.75, 0.25, 0.45, 0.70,
# 0.80, 0.35, 0.55, 0.20, 0.90), 5, 2)
# plot(c(0, 1), c(0, 1), type="n")
# polygon(pg[,1], pg[,2])
# P < matrix(runif(20000), 10000, 2)
# R < inpolygon(P[, 1], P[, 2], pg[, 1], pg[,2])
# clrs < ifelse(R, "red", "blue")
# points(P[, 1], P[, 2], pch = ".", col = clrs)## End(Not run)
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