Given a set of cartesian coordinates, this function determines which points belongs to the convex hull (or envelope) of the set.

isChull(x, y)

## Arguments

x A vector of x (or longitude) coordinates. A vector of y (or latitude) coordinates.

## Value

A numerical vector of the same length as x and y. 0 indicates that the corresponding point is not part of the convex hull of the set. Values >0 indicates that the corresponding point is part of the convex hull, and each value corresponds to the order of the point along the convex hull polygon.

## Examples

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