Question

I have a SpatialLines object representing roads and a SpatialPolygons object
containing cities.

I’d like to know how to overlay a SpatialLines object by a SpatialPolygons
object in R.

I’d like to know the Lines that passes over the two cities and which cities in?

Is it possible?

Answer 1

In general, overlays of spatial objects are handled by the over function from the sp package. In the Methods section of the documentation of over (?over) there is a list of methods for over, which does not include the combination of Lines and Polygons. Luckily, the documentation of over says that by installing the rgeos package these kind of methods are made available.