Get access to street data in iOS

Question

I have a graph G with n nodes. The graph is embedded in 2D space (so that there are well-defined angles and distances between each pair of nodes). Some nodes might be connected with edges to other nodes. Given a location L, this graph needs to be laid out on top of a map close to L, such that each node becomes a marker on a map, and such that there is a walkable path between each pair of connected of nodes. Since this will not be possible most of the time, I will allow the graph to be scaled/rotated and I will alow the distances and angles between nodes to be flexible within a certain range.

In order for me to write this specific algorithm, I would need to have some specific information about the streets near L. Does anybody know to get street data as a graph structure (so that I can get walkable paths)? I know the Google Maps API allows you to get directions between two points but I'm sure I cannot just keep getting directions without incurring any cost.

Edit: I've been reading a bit about OpenStreetMap API. It looks like this could be interesting. Maybe people can comment on this as well.

Answer 1

You can also check out these sites for osm and open gis data.

OpenStreetMap Extracts, here

OpenStreetMap derived data, here

GIS Datasets, here

in addition to these;

Planet.osm/diffs here

i hope it helps you...

Answer 2

The TIGER datasets offer a shape/line file for the USA, free. Lots of options including roads. https://www.census.gov/geo/maps-data/data/tiger-line.html