imclab / map-files

Common files for Javascript mapping with basic demographic data baked in

Map Files from Time Interactives

Common files for Javascript mapping with basic demographic data baked in

Source

All shapefiles are downloaded from the "2010 Census Demographic Profile 1 — Shapefile Format" section of the Census Department's TIGER/Line(R) Shapefiles Pre-joined with Demographic Data page.

• States
• Counties
• Congressional districts

Conversions

The TopoJSON files are produced using the GDAL library's ogr2ogr function and the TopoJSON command-line tool, as elegantly described in this StackOverflow response by Mike Bostock.

The large GeoJSON files produced in the intermedia stages of this conversion are preserved in the repo.

Requirements

• GDAL. Binaries are available for Windows and OSX. Linux machines can install with sudo apt-get install gdal-bin
• TopoJSON. Clone the respository or install using the Bower package manager.

Example command: SHP -> GeoJSON

ogr2ogr -f GeoJSON geojson/states.json shp/State_2010Census_DP1.shp

Properties to preserve

The shapefiles from the demographic profiles page come with about 250 data points, most of which we don't need. By default, we'll hang on to these:

• DP0010001: Total population
• DP0020001: Median age, both sexes
• DP0040001: Population 18+
• DP0110011: White, not Hispanic
• DP0110012: Black, not Hispanic
• DP0110013: American Indian, not Hispanic
• DP0110014: Asian, not Hispanic
• DP0110002: Hispanic or Latino

The files also come with some basic political and geographic data points we need to preserve:

• GEOID10: Geographic ID
• STUSPS10: State name
• NAME10: Name
• ALAND10: Land area
• AWATER10: Water area
• INTPTLAT10: Latitude of the internal point
• INTPTLON10: Longitude of the internal point

Example commands: State files

ogr2ogr -f GeoJSON geojson/states.json shp/State_2010Census_DP1.shp