3 ms·

awesome work, thanks for this. Where do you get the city block and neighborhoods shapes from?

• jacobn 12y ago
  Neighborhood shapes are from Zillow (link in the site footer on pages with neighborhoods), the city block shapes come from the Census. They have shapefiles for all their geographical entities (state, county, tract, block group, block) (I'm one of the devs)
  • dieg0 12y ago
    Right! I missed that Zillow reference... very cool to see they provide that data for free. We are working on a project that will be using open street maps and will also have heavy loads of data, we have geo spacial data on Arc Shapefiles but we are not sure yet on how to work with that yet, do you have any tips on that?
    • jrd79 12y ago
      We ended up using some random C library to parse the shapefiles into an easier to read text format of our own design, and then pulling them into packed binary files with an external index that we memory map in the code to maximize the speed. The system is all extremely custom and is highly optimized for write-once/read-many. Making even a tiny change to a single polygon means a full refresh that takes hours to complete.