# in.convex.hull: Determines if points are in the convex hull of a... In tripack: Triangulation of Irregularly Spaced Data

## Description

Given a triangulation `tri.obj` of n points in the plane, this subroutine returns a logical vector indicating if the points (x_i,y_i) are contained within the convex hull of `tri.obj`.

## Usage

 `1` ```in.convex.hull(tri.obj, x, y) ```

## Arguments

 `tri.obj` object of class `"tri"` `x` vector of x-coordinates of points to locate `y` vector of y-coordinates of points to locate

Logical vector.

A. Gebhardt

## References

R. J. Renka (1996). Algorithm 751: TRIPACK: a constrained two-dimensional Delaunay triangulation package. ACM Transactions on Mathematical Software. 22, 1-8.

`tri`, `print.tri`, `plot.tri`, `summary.tri`, `triangles`, `add.constraint`, `convex.hull`.
 ``` 1 2 3 4 5 6 7 8 9 10 11``` ```# example from TRIPACK: data(tritest) tr<-tri.mesh(tritest\$x,tritest\$y) in.convex.hull(tr,0.5,0.5) in.convex.hull(tr,c(0.5,-1,1),c(0.5,1,1)) # use a part of the quakes data set: data(quakes) quakes.part<-quakes[(quakes[,1]<=-10.78 & quakes[,1]>=-19.4 & quakes[,2]<=182.29 & quakes[,2]>=165.77),] q.tri<-tri.mesh(quakes.part\$lon, quakes.part\$lat, duplicate="remove") in.convex.hull(q.tri,quakes\$lon[990:1000],quakes\$lat[990:1000]) ```