Jenness Enterprises
Wildlife and Forestry Tools for ArcGIS Pro — Tool Reference
jennessent.com
Tool Reference › Corridor Designer Tools › Weighted Summary Statistics

Weighted Summary Statistics

Corridor Designer Tools · Evaluate Corridors · geoprocessing tool · by Jeff Jenness
Works at every ArcGIS Pro license level

Summary

Summarizes numeric attribute fields of a polyline or polygon feature class two ways, side by side: ordinary record statistics (each record one equal vote) and geometry-weighted statistics, where each record is weighted by its geodesic length (polylines) or area (polygons). For attributes describing a per-unit-landscape property — habitat suitability, canopy cover, resistance, road effects — the weighted statistics are the ecologically correct description of the system. An optional case field produces one set of statistics per class; a map layer's selection is honored. No Spatial Analyst needed.

Learn more About Corridor Design covers the descriptors used to evaluate and compare corridors. Metric 3 of the Corridor Evaluation Tutorial runs this tool on the parcels inside the corridor, by owner type, with the tutorial data (41 MB) available to download so you can follow along.

Why weighted statistics tell the truth

An ordinary mean answers “what is the value of an average mapping unit?” — a 1-hectare sliver counts exactly as much as a 5,000-hectare wilderness block. But the animal does not live on mapping units; it lives on the land. The area-weighted mean answers the ecological question: “what is the value of an average hectare?” — the expected value experienced by an animal placed anywhere on the landscape. When a habitat model scores a large block poor and a few small patches excellent, the unweighted mean is misleadingly optimistic; the weighted mean tells the truth about what most of the landscape is like.

The subdivision argument Polygon boundaries are usually artifacts of digitizing, tessellation, or unioning — not biological entities. Split one polygon into two identical halves and nothing about the ecosystem changes, yet every unweighted statistic changes, because that polygon now casts two votes. The weighted statistics are invariant to subdivision: however the same landscape is carved up, they come out the same. A statistic that changes when nothing real changed is describing your data structure, not your ecosystem.

A tour of the dialog

The example is the parcel-ownership run from the Corridor Evaluation Tutorial: a county parcel map clipped to the black bear corridor, two attribute fields summarized, one row of statistics per owner type.

The Corridor Designer Tools gallery open on the ribbon, with the Weighted Summary Statistics button, in the Evaluate Corridors row, outlined in blue
Where to find it: Weighted Summary Statistics is in the Evaluate Corridors row of the Corridor Designer Tools gallery, in the Corridor Designer Tools group of the Wildlife and Forestry tab.
The corridor between the Tumacacori and Santa Rita blocks filled with clipped parcel polygons: a dense mass of tiny lots at the western end near the highway, large irregular parcels through the middle, and a block of rectangular parcels toward the Santa Rita end
The input: the county parcel map clipped to the corridor, 1,564 parcel pieces. Tiny subdivision lots crowd the western end near the highway; big ranch and state parcels fill the middle.

The tutorial walks through why the clip comes first and how to read the two halves of the table.

The Weighted Summary Statistics dialog: input Black_Bear_Parcels, numeric fields Full Cash Value, Acreage and a joined MEAN suitability field, case field Owner Type, output table Black_Bear_Parcels_WeightedStats
Input features, one or more numeric fields, an optional case field, and the output table.
The output table: one row per owner type and field, with Sum, the record Mean (each record one equal vote), Standard Deviation, Variance and Median, then the Total area of Records Used in square meters leading into the area-weighted columns
The output: record statistics on the left, the area each row represents, then the area-weighted statistics to the right (scrolled off here; the tutorial shows the whole table).

ModelBuilder

A ModelBuilder diagram: Black_Bear_Parcels feeding into Weighted Summary Statistics, producing Black_Bear_Parcels_WeightedStats
Clipped corridor features in; the statistics table out.

Parameters

LabelExplanationData type
Input polyline or polygon featuresRequired · in_features The features to summarize; an active selection is honored. Feature Layer
Numeric field(s) to summarizeRequired · fields One statistics set per field. Multiple Value
Case fieldOptional · case_field One row of statistics per class (e.g. per land-cover type, per owner). Field
Output tableRequired · out_table The paired record and geometry-weighted statistics. A table written to a folder is a dBASE (.dbf) table, which cannot store nulls: a statistic that is undefined there, such as the standard deviation of a single record, is written as −999. In a geodatabase table it is null. Table

Python

import arcpy
arcpy.ImportToolbox(r"C:\path\to\JennessEnterprisesTools.pyt")  # your install path
arcpy.jenness.WeightedSummaryStatistics(
    in_features="Corridor_LandCover_Clip",
    fields="Suitability;CanopyPct",
    case_field="Ownership",
    out_table=r"D:\corr.gdb\corridor_stats")

Recommended citation

Jenness, J., D. Majka and P. Beier. 2026. Weighted Summary Statistics. Wildlife and Forestry Tools add-in for ArcGIS Pro, v. 1.99 (September 2026). Jenness Enterprises. Available at: https://github.com/JeffJenness/Wildlife_Tools.

Credits and references

By Jeff Jenness, Jenness Enterprises (www.jennessent.com), in the lineage of the CorridorDesigner Evaluation Tools' statistics tools by Jenness, Majka and Beier.

Licensing information

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