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Tool Reference › Home Range › LoCoH (Standard)

Local Convex Hull (LoCoH) — Standard

Home Range · geoprocessing tool · by Jeff Jenness
Works at every ArcGIS Pro license level
Learn more About LoCoH home-range analysis covers the ideas shared by all three LoCoH tools — utilization distributions and isopleths, how local hulls are built and merged, why hulls honor hard boundaries that kernels smooth over, and how to choose the governing parameter. Home-range estimation is also a wildlife module of Jeff's GIS training course, with videos and lab exercises using these tools.

Summary

Estimates an animal's home range and utilization distribution by the Standard (fixed-k) Local Convex Hull method of Getz and Wilmers (2004): every location's local hull is the convex hull of that point and its k − 1 nearest neighbors. Hulls are sorted by area from smallest to largest and merged cumulatively into density isopleths — the 95% isopleth approximates the home-range boundary while excluding outlying excursions. Outputs are the dissolved cumulative isopleths and, optionally, the individual hulls.

How k shapes the hulls

k counts the points in each hull, including the focal point itself — so each hull is a point plus its k − 1 nearest neighbors, and k must be at least 3 (the smallest hull that can be a polygon) and no greater than the number of points. Small k produces tighter, more fragmented hulls that capture fine structure and hard boundaries — rivers, cliffs, habitat edges — while large k produces smoother, more contiguous ranges; k equal to the number of points reduces to the minimum convex polygon.

Choosing k. Getz et al. (2007) suggest k = √n as a starting value — about 10 for a hundred locations. From there, the minimum spurious hole covering rule guides refinement: pick the smallest k that fills the holes you judge spurious, keeping the real ones. Plotting isopleth area against k across a handful of runs shows where the area levels off — and begins to over-inflate — which is the empirical procedure the T-LoCoH package recommends (Lyons, Turner and Getz 2013). You do not have to build those runs by hand: our LoCoH Parameter Explorer window sweeps k across a range of values in one click and charts the 50%, 75% and 95% isopleth areas against it, with k₁ = √n marked — run it first, then bring the k it suggests to this tool. Screen out obvious location errors first; LoCoH is sensitive to outliers.

Three aerial panels of the same canyon-dwelling species locations under Standard LoCoH at k of 10, 30 and 80: tight canyon-hugging isopleths at 10, a smoother range bridging the canyon bend at 30, and a nearly convex shape at 80
One cloud, three values of k — our canyon-dwelling species from the Concave Hull page. At the recommended starting value (k = √n ≈ 10, left) the isopleths hug the canyon; at k = 30 the range smooths and begins to bridge the canyon's bend; at k = 80 it is nearly the convex hull.

What you get

The primary output holds the dissolved cumulative isopleths: each feature stores its dissolved area (Area), the number of input points it encloses (Point_Count), the proportion of all points (Point_Proportion), and the point density in points per square kilometer (Pts_per_SqKm) — the feature nearest 0.95 is the conventional home range, the one nearest 0.50 the core areas. The optional second output holds the individual local hulls, each with its own area, its own point count (always k) and proportion, and its own point density. Geographic inputs use Haversine distances and WGS84 spheroidal areas; projected inputs use planar measures. Area is in square meters for geographic inputs and in square map units for projected inputs. The Output Coordinate System environment is honored for the final polygons.

A tour of the dialog

A run needs the points, k, and an output name for the cumulative isopleths; the individual hulls are one optional output more.

The Home Range Tools gallery open on the ribbon, with the LoCoH (Standard) button, in the Local Convex Hulls row, outlined in blue
Where to find it: LoCoH (Standard) is in the Local Convex Hulls row of the Home Range Tools gallery, in the Home Range group of the Wildlife and Forestry tab.
The Standard LoCoH geoprocessing pane with Owl 6 points as input and k set to 30, beside forested aerial imagery where the cumulative isopleths shade from nearly black core areas outward to a pale full range, with red day and blue night locations on top
The dialog and its result on Mexican spotted owl #6 — the same owl that stars in the About-page walkthrough — at k = 30, the √n starting value for this dataset. Darkest isopleths enclose the smallest share of the points: the owl's core areas.

ModelBuilder

Both outputs chain onward in a model — the isopleth polygons feed clip, overlay, or reporting steps directly, and a Select on Point_Proportion pulls the 95% or 50% isopleth out of the stack for the next tool.

A ModelBuilder diagram: the species locations feeding the Local Convex Hull Standard tool, with the cumulative isopleths and the optional individual hulls as outputs
The tool in a model: locations in, cumulative isopleths (and optionally the individual hulls) out.

Parameters

LabelExplanationData type
Input point featuresRequired · in_features The point features (GPS or VHF telemetry fixes, for example) the local hulls are built from. Geographic or projected; empty geometries are ignored. Every point of a multipoint feature is used. Feature Layer
Number of nearest neighbors (k)Required · k Points per hull, including the focal point — each hull is a point plus its k−1 nearest neighbors. At least 3, at most the number of points. Long
Cumulative LoCoH [Standard] HullsRequired · out_isopleths The dissolved cumulative isopleths, each with Area, Point_Count, Point_Proportion, and Pts_per_SqKm. Feature Class
Output individual hulls (optional)Optional · out_hulls The individual local convex hulls, each with its own area, point count, proportion and density. Feature Class

Python

A 10-neighbor Standard LoCoH with both outputs:

import arcpy
arcpy.ImportToolbox(r"C:\path\to\JennessEnterprisesTools.pyt")  # your install path
arcpy.jenness.LoCoHStandard(
    in_features=r"D:\data\telemetry.gdb\owl_fixes",
    k=10,
    out_isopleths=r"D:\data\telemetry.gdb\owl_isopleths_k10",
    out_hulls=r"D:\data\telemetry.gdb\owl_hulls_k10")

Recommended citation

Jenness, J. 2026. Local Convex Hull (LoCoH) — Standard. Wildlife and Forestry Tools add-in for ArcGIS Pro, v. 1.98 (September 2026). Jenness Enterprises. Available at: https://github.com/JeffJenness/Wildlife_Tools.

Credits and references

By Jeff Jenness, Jenness Enterprises (www.jennessent.com), implementing the fixed-k LoCoH method of Getz and Wilmers. Full references on the About LoCoH page.

Licensing information

Works at every ArcGIS Pro license level (Basic, Standard, Advanced). No extension licenses are required.