what happens when a character is in an interior and he summons another? do they get the marker at the house's door?
If the wielder is in a house, the entrance of that house is marked and the address of the house is show to the subject.
If the wielder is in, e.g.: Folnkirk, and the subject is in Angel Pine, the nearest sewer manhole is marked. Then when the subject enters the sewer, the passage to Folnkirk is marked.
All interiors are pretty much covered.