Michal Migurski's notebook, listening post, and soapbox. Subscribe to this blog. Check out the rest of my site as well.

Jul 19, 2011 6:08pm

help make pre-quake san francisco seeable

Take five minutes, and help place a few of these historic Sanborn maps of pre-earthquake San Francisco in their modern locations.

Maptcha is a thing I’ve been poking at since simultaneously finding the newly-rescanned 1905 San Francisco Sanborn Insurance Atlas via John “Burrito Justice” and being tipped off to Paper.js by Tom Carden. It’s a simple, minimal-code interface doing rough placements of historical maps on modern geography, and I’ve been getting completely amazing feedback from all the people who’ve checked out early versions (thanks Paul, Ryan, Cal, Boris, Heather, Tim, Matt, Schuyler, Ian, Tom, Eric and especially George).

Historical maps come with all the usual bibliographic context, but almost no geographic context: the point-to-point correspondences that make it possible to overlay them on modern maps. Tim, Schuyler and Shekhar have been doing some fantastic work in this area with map librarian Matt Knutzen at the New York Public Library on the NYPL Map Warper, something we were lucky enough to participate in last year. The release of the new Sanborn scans was an out-of-band inspiration along these same lines, and an opportunity to test some ideas that wouldn’t quite fit in the NYPL context.

  • All of the Sanborn maps were at a similar scale and time period, which meant that we could ask people to look for cross-streets and be mostly confident that they still exist in a modern geocoder.
  • There are a limited number (700 or so), making it possible to create a bounded task with a clear end-point. You can finish it, an important feature for crowdsourcing initiatives that might not have a realistic end.
  • We know they’re roughly conformal despite the massive distortions in street width. Most of the time, it’s fine to make the north arrow point up and fiddle with the size to get a good-enough placement. This has the added bonus of not bringing GDALwarp into the mix—it’s made of Canadian geo-magic but imposes its own technical burdens.

A lot of these specific adaptations come from the Internet Archive’s George Oates, whose comments on my initial UI sketches helped greatly clarify some of the knowns we’ve got to hand in an atlas like this one.

I’m not sure what happens to the output data from this process. Certainly it will be made available in some open format that links geographic placement back to the original scans in the Rumsey collection. John’s been nudging me toward a second-pass, more advanced UI that can help refine all these rough placements to something more precise that can help answer real questions about San Francisco’s history immediately prior to the earthquake of 1906. I’ve long been curious about the train line that led to such a gorgeous stripe of scar tissue through the Mission, but what about all the extra information you can glean from business and construction listings as detailed as these?

Anyway, go give it a shot. Let’s see if we can’t get all these images placed.

Comments (4)

  1. Here's another thought, since you've brought this up anyway: What if you had a Google Maps like tool, but instead of simply being able to read the map in two or three dimensions, you can also travel back in time. For the most part, cities keep public maps and the census keeps geological surveys, so this should be doable at least to a precision of 10 years, if not less.

    Posted by Luftmensch on Tuesday, July 19 2011 12:12pm UTC

  2. Mike, here's a huuuuge stitch-up of the Southern Pacific line through the Mission & SOMA. It's a mash-up of contemporary sat imagery + Sanborn + historical photos: http://www.xrg.us/missionrailroad/

    Posted by TS on Tuesday, July 19 2011 5:01pm UTC

  3. Given how quickly the public (including myself) tore through these maps, I think it would be more than worthwhile to take another, much more accurate pass at it. I know nothing about the coding necessary to pull it off, but I think we really need to be able to more accurately locate individually cropped blocks from these maps. I am pretty sure I'd waste a few hours at that. I already put in a surprising amount of time researching historic street naming schemes today. Also, the random feature keeps it interesting, but negates the "expertise" one develops on certain neighborhoods while placing the maps. Furthermore, since construction of the San Francisco and San Jose Railroad started in 1861, its right of way predates most development in the Mission, therefore, I am not sure if "scar" is the right metaphor since the city grew up along the tracks. It certainly speaks to the durability of property lines. Something I remember one of my geography professors pointing out once.

    Posted by Randolph Ruiz on Wednesday, July 20 2011 6:34am UTC

  4. Hrm... Did we lose that Google+ thread?

    Posted by George Oates on Monday, September 12 2011 10:13pm UTC

Sorry, no new comments on old posts.

June 2022
Su M Tu W Th F Sa

Recent Entries

  1. Mapping Remote Roads with OpenStreetMap, RapiD, and QGIS
  2. How It’s Made: A PlanScore Predictive Model for Partisan Elections
  3. Micromobility Data Policies: A Survey of City Needs
  4. Open Precinct Data
  5. Scoring Pennsylvania
  6. Coming To A Street Near You: Help Remix Create a New Tool for Street Designers
  7. planscore: a project to score gerrymandered district plans
  8. blog all dog-eared pages: human transit
  9. the levity of serverlessness
  10. three open data projects: openstreetmap, openaddresses, and who’s on first
  11. building up redistricting data for North Carolina
  12. district plans by the hundredweight
  13. baby steps towards measuring the efficiency gap
  14. things I’ve recently learned about legislative redistricting
  15. oh no
  16. landsat satellite imagery is easy to use
  17. openstreetmap: robots, crisis, and craft mappers
  18. quoted in the news
  19. dockering address data
  20. blog all dog-eared pages: the best and the brightest