How does physical geography map to mental geography? How does personal experience intersect with group and public experience, or analog cartography with digital? For Lines Made by Walking, five epic group excursions departed from the same site, StoreFrontLab, and ended at different points along the water, going counter-clockwise around the perimeter of San Francisco. Over 100 people participated in the walks, sharing and spreading their stories and observations across the city. This talk by Ilyse Iris Magy was part of the session "Mapping Public Intensities: Emerging Tools for Critical Urban Practices" at the re:publica conference in Berlin.