We worked on tracing, improving, and validating over 173,447 building footprints in OpenStreetMap, focusing on San Francisco. We mapped buildings in two cities: Menlo Park and Mountain View. We traced each building by hand, using satellite images and the official San Francisco building map as guides. We focused on quality, ensuring that we preserved good edits made previously, communicating with local mappers whenever possible, and correcting shapes where necessary.

In order to do mapping work easier and faster, we used the building plugin that is available on Java OpenStreetMap Editor (JOSM).

Total area mapped in San Francisco.