Mapsnap: Automated Georeferencing for Historic Sanborn Insurance Maps
a day ago
- Sanborn maps provide block-by-block historical urban details from 1870–1960, originally for insurance assessment.
- The program mapsnap automatically georeferences Sanborn maps by using OCR to detect street labels and extrapolate intersections.
- Street labels are detected via EasyOCR, then paired with OpenStreetMap data to create ground control points.
- A RANSAC algorithm filters out unreliable ground control points to achieve accurate georeferencing.
- The system handles up to 50% noise but struggles with curved streets, illegible labels, or changed streets.