By Ruben Lopez Mendoza on June 13 2014

Our data team has been busy tracing building footprints in San Francisco. The effort is not finalized but so far we have spent many hours tracing, improving and validating over 114,000 building footprints. Here is an animation of the progress we have made.

animated gif showing building progress

Mapping buildings — progress in San Francisco.

All buildings are traced by hand from a combination of satellite imagery and the official San Francisco building footprint layer. While the building footprint layer is too inaccurate for an import, it serves as a great reference layer to guide tracing. Our topmost priority is quality. We have taken particular care to respect existing edits, reaching out to individual mappers on the ground where possible and improving existing geometries where we found clear opportunities.

This is an ongoing effort, join us tracing, or post feedback on Github — we’d love to hear from you.