addVertices

Add New Vertices to a Linear Network

Adds new vertices to a linear network at specified locations outside the network.

Usage

addVertices(L, X, join=NULL, joinmarks=NULL)

Details

This function adds new vertices to an existing linear network L, at specified locations X outside the network.

The argument L can be either a linear network (class "linnet") or some other object that includes a linear network.

The new vertex locations are points outside the network, specified as a point pattern X (object of class "ppp").

The argument join specifies how to join the new vertices to the existing network.

• If join=NULL (the default), the new vertices are simply added to the list of network vertices without being joined to the rest of the network.

• If join is a vector of integers, then these are taken to be indices of existing vertices of L in the order given in V = vertices(L). Then each new vertex X[i] will be joined to an existing vertex V[j] where j = join[i]. Each new vertex is joined to exactly one existing vertex.

• If join="vertices" then each new vertex X[i] is joined to the nearest existing vertex V[j]. Each new vertex is joined to exactly one existing vertex.

• If join="nearest" then each new vertex is projected to the nearest location along on the network; these locations are inserted as new vertices of L; and then each vertex X[i] is joined to the corresponding projected point. Each new vertex is joined to exactly one newly-inserted vertex.

• If join is a point pattern on a network (class "lpp"), it must be defined on the same network as L and it must consist of the same number of points as X. The points of join will be inserted as new vertices of L, and then each vertex X[i] is joined to the corresponding point join[i]. Each new vertex is joined to exactly one newly-inserted vertex.

The result is the modified object, with an attribute "id" such that the ith added vertex has become the id[i]th vertex of the new network.

See Also

insertVertices to insert vertices along an existing network.

as.lpp, linnet, methods.linnet, joinVertices, thinNetwork.

Aliases

• addVertices

Examples

# NOT RUN {
   opa <- par(mfrow=c(1,3))
   L <- simplenet
   X <- runifpoint(20, Window(simplenet))
   plot(L)
   plot(X, add=TRUE, cols="green", pch=16, cex=2)
   plot(addVertices(L, X, "nearest"), col="red")
   plot(L, add=TRUE, col="grey", lwd=3)
   plot(X, add=TRUE, cols="green", pch=16, cex=2)
   plot(addVertices(L, X, "vertices"), col="red")
   plot(L, add=TRUE, col="grey", lwd=3)
   plot(X, add=TRUE, cols="green", pch=16, cex=2)
   par(opa)
# }