AI helps add 10,000 more photos to OldNYC

The OldNYC historic photo map grew from 39,000 to 49,000 photos through three major improvements made in 2024. GPT-4o was used to extract location data from photo descriptions, locating ~6,000 additional photos and raising the geocoding accuracy to 87%. OCR was rebuilt using gpt-4o-mini, dramatically improving transcription quality over the old Ocropus pipeline. The site also migrated from Google Maps to OpenStreetMap vector tiles and MapLibre to avoid ~$35/month in new Google Maps fees, while gaining the ability to customize the map to remove modern infrastructure like highways that didn't exist in the 1930s.