# Test Whether Points are Inside a `"gpc.poly"`

Polygon

`inside.gpc.poly.Rd`

Same as, e.g., `inside.owin`

from package spatstat.geom
and `point.in.polygon`

from package sp,
i.e., test whether points lie inside or outside a given polygon.
Actually, the method for `"gpc.poly"`

documented here internally uses
the `point.in.polygon`

function.

## Arguments

- x,y
numeric vectors of coordinates of the points to be tested. The coordinates can be supplied in any form accepted by

`xy.coords`

.- polyregion
an object of class

`"gpc.poly"`

. It is checked if the points specified through`x`

and`y`

fall into this polygonal region.- mode.checked
passed to

`point.in.polygon`

.

## Details

The nodes and edges of (non-hole) polygons are treated as being inside.
Points that fall *strictly* inside holes are treated as being outside
of the polygon.

## Value

Logical vector whose `i`

th entry is `TRUE`

if the corresponding
point `(x[i],y[i])`

is inside `polyregion`

.

## Examples

```
if (surveillance.options("gpclib") && requireNamespace("gpclib")) {
poly <- discpoly(c(0.5,0.5), 0.5, npoly=4, class="gpc.poly")
pts <- cbind(x=runif(50), y=runif(50))
plot(poly)
points(pts, col=1+inside.gpc.poly(pts, polyregion=poly))
}
```