Nicely done.
I'd love it if it also supported modifying the URLs, since they are so readable. For example, if I delete the 199 from the end of your URL [1], it should still show me Valencia St. on the map. However, in its current state, I don't think the app parses any incoming URLs from the location field.
[1] http://nice-map-urls.herokuapp.com/united-states/california/...
[2] https://maps.google.com/maps?q=199+Valencia+Street,+San+Fran...
[I attached google's original link just for reference]