equipop 1.8.1

k-nearest neighbour contexts/neighbourhoods on gridded and hexagonal data: bespoke neighbourhoods, friction growth, distance decay, statistics and segregation measures

EquiPop (Python)

k-nearest neighbour contexts/neighbourhoods on gridded and hexagonal data: bespoke neighbourhoods, friction-aware growth, distance decay, neighbourhood statistics and segregation measures - for very large datasets.

EquiPop finds, for every populated location, the k nearest individuals (by cumulative population count, expanding over a uniform grid) and reports the composition of that individualised neighbourhood. The gridded design means one pre-computed distance ordering serves every origin, which is what makes millions of locations feasible.

The EquiPop family

This is the first Python implementation. Its relatives: the original C# EquiPop (three generations, two public releases; radial and Flow models, downloadable via Uppsala University) and an R version covering I/O and the basic k-NN parts. This Python version additionally carries friction growth, five decay models, exact neighbourhood statistics (mean/median/SD/SE/Gini/entropy), segregation indices, hexagonal grids, area aggregation and metadata logging.

Install

pip install equipop            # core
pip install equipop[geo,io,viz]  # shapefiles/rasters, Excel/SPSS, maps

Quick start

import pandas as pd
from equipop import build_cells, run_knn_stats

df = pd.read_csv("individuals.csv")        # one row per individual
cd = build_cells(df, e_col="X", n_col="Y",
                 binary_vars=["treated"], value_vars=["income"],
                 unit_size=100)
res = run_knn_stats(cd, k_values=[100, 400, 1600, 6400],
                    stats={"treated": ["ratio"],
                           "income": ["mean", "median", "gini"]})

For aggregated counts at national scale use the vectorised run_knn_counts; for friction-constrained growth run_knn_friction; for segregation profiles seg_profile; for policy-area reporting aggregate_output; for quick maps map_output. See MANUAL_TOPICS.md.

Repository: https://github.com/GeoJohnSwe/EquiPop

Citing

Please cite the software and the methods you use - see CITATION.cff. Core reference: Östh (2014), Introducing the EquiPop software, Uppsala University. Segregation measures: Östh, Clark & Malmberg (2015), Geographical Analysis 47(1). Decay parameters: Östh, Lyhagen & Reggiani (2016), EJTIR 16(2). Friction growth: Östh & Türk (2020), Handbook of Urban Segregation. Decay profiles in application: Türk, Östh, Kourtit & Nijkamp (2026), Journal of Urban Mobility 9.

License

MIT. Attribution through citation is warmly requested (see above).