X and Y should be tessellations on a linear network
(objects of class "lintess") and should be defined on the
same network. The algorithm finds the common refinement of the
two tessellations. Each tile in the resulting tessellation
is the intersection of a tile of X with a tile of Y.
Alternatively, one of the arguments X or Y
can be a two-dimensional tessellation (object of class
"tess") while the other argument is a network or a tessellation
on a network. The two-dimensional tessellation will be intersected
with the network to produce a tessellation on the network, then
intersected with the other tessellation on the network.