sdc-census10to20

Redistribute 2010-2019 census data onto 2020 census boundaries.

This package is the Python port of the R package sdc.census10to20. It is used by the Social Data Commons pipelines to make tract- and block-group-level data comparable across the boundary changes that occurred between the 2010 and 2020 decennial censuses.

Install

pip install sdc-census10to20

What it does

Census tract and block-group boundaries change between decennial censuses. A single 2010 tract may become a single 2020 tract with the same boundary (same), be split into several 2020 tracts whose union equals the original (split), or have its boundary shift so it only partially overlaps with one or more 2020 tracts (moved).

For each case this package can:

1. Build a crosswalk from the official Census relationship files (get_2010_2020_bound_changes, create_crosswalk).
2. Redistribute values from 2010 boundaries onto 2020 boundaries — pass-through for same/split, area-proportional for moved (convert_2010_to_2020_bounds).
3. Take a long-format dataset spanning multiple years and emit both the original _geo10-suffixed measure and the redistributed _geo20-suffixed measure (standardize_all).

See the Getting Started article for a worked Virginia example.