If I wanted to do my own walkability survey of my city, what tools could I use? I have map data from OpenStreetMap, but I have to consider that streets have two sides (which aren't always accessible from the other side of the street). I guess I need to make a sidewalk map.
I'd like to use path-finding algorithms against the data to provide walking directions that avoid sections of streets with poor walkability. Some blocks have sidewalks, some don't, and some streets have a sidewalk on one side but are too busy to cross. The directions would cross the highway at places where it's easier--very easy at the crosswalk, hard at several other streets, impossible at a few streets.
I know that weighted path-finding algorithms exist. I'm just wondering how to create this data. I've toyed with taking a map image, putting it in Inkscape, turning on grid lines, and overlaying paths along the sidewalks. With the grid lines, the points of paths connect for path-finding. Path color indicates difficulty of walking. Aside from the path-finding, it'd be a good map to show walkability in town.
Anyone have any ideas?