For scribes in medieval Europe, parchment on which writing appeared was sometimes scraped clean to create a new writing surface. Not infrequently, however, the old writing continued to show through, resulting in a palimpsest – i.e., layers of overlapping writing that suggested a parchment’s history of uses.
Urban environments can be like palimpsests, in which the viewer can sometimes discern visual cues for successive uses of the same location over time. And sometimes, a bit of historical investigation can help make the palimpsest of the San Francisco cityscape emerge.
Todd Lappin of Telstar Logistics recently collaborated with the blogger of Burrito Justice (who uses the moniker “johnny0″) to identify sites on Potrero Hill related to the location of the former Seals Stadium – San Francisco’s minor league baseball stadium from 1931 until 1959.
Lappin and johnny0 initially consulted Google Earth in an attempt to identify the exact location of the former baseball stadium. Specifically, they used the historical map overlay – a feature introduced by Google in 2006 in which selected historical maps can be displayed, palimpsest-like, over contemporary maps. Currently, historical maps available for San Francisco on Google Earth include maps from 1946 – when Seals Stadium was still standing. Lappin and johnny0 discovered, however, that the historical overlay feature did not provide them with the degree of precision they wanted in superimposing 1946 map features over contemporary San Francisco.
This prompted them to turn to the fire insurance maps originally produced by the Sanborn Map Company of Pelham, New York. johnny0 had first encountered Sanborn maps of San Francisco on the SFGenealogy website.
Because Google Earth has a feature that allows users to overlay their own content on top of Google Earth maps, johnny0 and Lappin managed to superimpose a Sanborn map of Seals Stadium on top of a Google Earth map of Potrero Hill.
Satisfied with the precision of their palimpsest, Lappin went to Potrero Hill to mark the former locations of the four bases of Seals Stadium. Using blue tape, he marked the sites as they exist in the current shopping center on 16th Street: home base and first base inside an Office Depot store, and second and third base inside a Safeway grocery store.
Lappin and johnny0 posted reports of their investigation on the Burrito Justice and Laughing Squid blogs. As part of their posts, they included pictures they had taken of the current Potrero Hill site (including pictures of the sites identified as the former locations of the bases), as well as images taken from the online Historical Photograph Collection of the San Francisco History Center.
When I’d asked johnny0 and Lappin what had motivated their project, both of them spoke to the question of how changing urban landscapes impact the organization of community life. As Lapin put it,
“It’s fascinating to me to think that a place like that [Seals Stadium] can exist, but then disappear, leaving no trace. It’s as if we didn’t have any ruins of Roman amphitheaters. That would be a tragedy, because it means we would never know about a telling aspect of their community life. The fact that so many people have no idea that there used to be a ballpark on the Safeway site feels much the same way to me. Only, it’s a sense of community life in the Mission that’s been lost.”
johnny0 pointed to future uses of this kind of work when he said,
“I think it’s extraordinarily valuable to have the historical perspective on how a neighborhood came to be… to enable the community to continue to grow.”