NHGISXWALK

Spatio-temporal NHGIS Crosswalks

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This project will eventually be transferred to the IPUMS project space.

This pacakge allows for the generation of temporal crosswalks of census geographic data built from the smallest intersecting units (atoms). Each row in a crosswalk represents a single atom and is comprised of a source ID (geo+year+gj), a target ID (geo+year+gj), and at least one column of weights. An example of a source ID is bgp1990gj (block group parts from 1990) and an example of a target ID is tr1990gj (tracts from 2010) — see notebooks/data-subset-sample-workflow-bgp1990tr2010.ipynb for the nhgis_bgp1990gj_to_tr1990gj crosswalk extract of Delaware. The weights are the interpolated proportions of source attributes that are are calculated as being within the target units. For a description of the algorithmic workflow see the General Crosswalk Construction Framework. Data from 1990 poses a specific problem due to the US Census Bureau not explicitly including blocks with no population/housing units in the summary files (SF1). For a description of the algorithmic workflow in the 1990 “no data” scenarios see Handling 1990 No-Data Blocks in Crosswalks. For more information of the base crosswalks see their technical details. For further description see Schroeder (2007).

Currently supported crosswalks include:

source target
1990 block group parts 2010 counties
2000 block group parts 2010 counties
1990 block group parts 2010 tracts
2000 block group parts 2010 tracts
1990 block group parts 2010 block groups
2000 block group parts 2010 block groups

Planned supported crosswalks include:

source target
1990 block group parts 2012 tracts
2000 block group parts 2012 tracts
1990 block group parts 2012 block groups
2000 block group parts 2012 block groups

Examples

Resources

Installation

Currently nhgisxwalk officially supports Python 3.6, 3.7, and 3.8. Please make sure that you are operating in a Python >= 3.6 environment. Install the most current development version of nhgisxwalk by running:

$ pip install git+https://github.com/jGaboardi/nhgisxwalk

Contribute

NHGISXWALK is under active development and contributors are welcome. If you have any suggestions, feature requests, or bug reports, please open new issues on GitHub. To submit patches, please review the nhgisxwalk contributing guidelines before opening a pull request.

Support

If you are having issues, please create an issue.

Citations

If you use nhgisxwalk in a scientific publication, we would appreciate using the following citations:

License

The package is licensed under the BSD 3-Clause license.

Funding

This project is funded through:

National Science Foundation Award #1825768: National Historical Geographic Information System