I am writing a re-districting application where I want to be able to create US voting districts based on geographic coordinate population data. In a perfect world, I would have the population for each house and the house's geographic coordinates. I am guessing that per house data is not likely to be available. What is the lowest level available? Blocks? Block groups?
I located a US census website which contains population data for block groups. Is this the finest granularity available for 2010 census data?
My end goal is to implement the shortest splitline algorithm for districting with 2010 census data. My intention is to slice up polygons using the shortest splitline according to the best population numbers relating to latitude/longitude coordinates I can find for people in the polygon.
Best Answer
For privacy reasons, personally-identifying house-by-house data from the Decennial Census are not available until 72 years after being recorded. Census Blocks are the highest spatial resolution geography for which more recent Decennial Census data are available.
If you only want Census Block populations for a couple of counties, use the Census Factfinder. Choose the table you want (P1 has basic population count) and the desired geography (e.g. All Blocks within Middlesex County, Massachusetts). You'll probably want to download it as a .csv for further processing.
If you want Census Block populations for a much larger swath of the United States, you are in for a world of hurt. You need to jump through a lot of hoops in order to overcome filesize limitations in most database software. The Summary File 1 page has more information.