In OpenStreetMap, paths for foot traffic such as park trails and sidewalks can be modeled in very similar ways. Any path intended for foot traffic can be tagged as highway=footway. This includes sidewalks, except that sidewalks should also have the footway=sidewalk tag. This allows for easy differentiation between sidewalks and other types of foot paths, which can help in styling a map.
Untagged sidewalks render like trails or other footpaths (left) Tagged sidewalks flow together (right)
Sometimes sidewalks in OpenStreetMap are not mapped properly, which results in sidewalks that look like regular foot paths. For well designed maps, we want to make sure sidewalks are mapped correctly - globally.
Finding all sidewalks
The good news is that this issue is usually straightforward for anyone to fix, because a sidewalk can often be identified from satellite imagery. The trick is to quickly find which sidewalks are mapped incorrectly. I’m using Turf, Tile Reduce, and OSM QA tiles to analyze the world’s road networks and highlight footways that appear to be sidewalks, but aren’t tagged as such.
To fix sidewalks, we created an interactive map to select potential sidewalks quickly for editing. Simply zoom to an area with highlighted sidewalks (green), click on one of them and then select your favorite OpenStreetMap editor.