# whichhalfplane

From spatstat v1.55-1
by Adrian Baddeley

##### Test Which Side of Infinite Line a Point Falls On

Given an infinite line and a spatial point location, determine which side of the line the point falls on.

##### Usage

`whichhalfplane(L, x, y = NULL)`

##### Arguments

- L
Object of class

`"infline"`

specifying one or more infinite straight lines in two dimensions.- x,y
Arguments acceptable to

`xy.coords`

specifying the locations of the points.

##### Details

An infinite line \(L\) divides the two-dimensional plane into
two half-planes. This function returns a matrix `M`

of logical values
in which `M[i,j] = TRUE`

if the `j`

th spatial point
lies below or to the left of the `i`

th line.

##### Value

A logical matrix.

##### See Also

##### Examples

```
# NOT RUN {
L <- infline(p=runif(3), theta=runif(3, max=2*pi))
X <- runifpoint(4)
whichhalfplane(L, X)
# }
```

*Documentation reproduced from package spatstat, version 1.55-1, License: GPL (>= 2)*

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