crossdist(X, Y, ...)[i,j] entry is the distance
  from the i-th thing in the first dataset
  to the j-th thing in the second dataset.X and Y
  (representing either two point patterns or
  two line segment patterns)
  crossdist computes the Euclidean distance from each thing
  in the first dataset to each thing in the second dataset,
  and returns a matrix containing these distances.  The function crossdist is generic, with
  methods for point patterns (objects of class "ppp"),
  line segment patterns (objects of class "psp"),
  and a default method. See the documentation for
  crossdist.ppp,
  crossdist.psp or
  crossdist.default for further details.
crossdist.ppp,
  crossdist.psp,
  crossdist.default,
  pairdist,
  nndist