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Tool Reference › Corridor Designer Tools › Histograms and Statistics

Histograms and Statistics

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

Summary

An interactive window for exploring the distributions behind the summary numbers: histograms and statistics of one or several datasets at once — attribute fields of features (weighted by geodesic length or area where that is the honest weighting), raster cell values, or categorical data such as land-cover classes and owner types — drawn as grouped bars with smooth weighted kernel-density overlays. Where Weighted Summary Statistics gives you the numbers in a table, this window shows the shapes: is the suitability inside the corridor high-and-narrow or a bimodal mix of excellent and awful that happens to average well? Its most powerful use is comparing a biologically optimal corridor with a proposed alternative: the same habitat factor or suitability model clipped to each, drawn on one chart as percentages, shows at a glance where the alternative falls short and by how much.

Learn more About Corridor Design covers the descriptors used to evaluate and compare corridors. Metric 3 of the Corridor Evaluation Tutorial reads the distributions inside the black bear corridor with this window, and Metric 4 sets them against a proposed alternative corridor, with the tutorial data (41 MB) available to download so you can follow along.

Comparing a corridor with its alternatives

A corridor model produces the biologically best route, and sooner or later someone proposes a different one: a route that avoids a landowner, follows a planned easement, or costs less to conserve. The question is what the species gives up, and this window answers it directly. Load the same field from two or more corridor polygons — or the habitat suitability values, or any habitat factor, clipped to each corridor — and their distributions sit side by side in one chart. Two corridors can share a mean while one hides a long tail of near-zero habitat; the histogram shows it instantly, and shown as percentages the comparison is fair even when one corridor is several times the size of the other. The chart places onto a layout via the suite's standard layout-first Add-to-Layout, and the binned tables export for further work, so the comparison goes into the report as evidence rather than as a claim.

A tour of the window

The example is the suitability comparison from the Corridor Evaluation Tutorial: one attribute field of a parcel layer added twice, once weighted by parcel area and once with each parcel counting equally, so the two distributions can be compared on the same axes. That page walks through adding the datasets, the native-units trap, and how to read the result; this page covers the rest of the window.

The Corridor Designer Tools gallery open on the ribbon, with the Histograms and Statistics button, in the Evaluate Corridors row, outlined in blue
Where to find it: Histograms and 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 Add Data to Histogram dialog: layer Black_Bear_Parcels, value field Black_Bear_HSI_per_Parcel.MEAN, all records, Weight each feature by its geodesic size checked, Clip to polygon set to Black Bear 2% Corridor, and the dataset name
Add Data...: a layer or table (or a raster), the field, whether to use only selected records, whether to weight each feature by its geodesic area or length, an optional clip polygon, and the name the legend will show. Any number of datasets can be stacked on one chart.

A definition query on a layer or table is always honored. The window reads the records the layer shows, so all records means all of those, and a selection is taken from among them. The clip polygon layer is read the same way.

The Histograms and Habitat Suitability Statistics window: chart with two histograms and density curves on the left; on the right the Chart group with title, axis labels, legend, reference lines and Fonts; the Bins group with bin count, min, max, automatic range and gap; the Y axis group with units and Show Y values as percentages; the Density curves group with Curves only and Smoothness; and the Datasets list with Rename, Color, Bars on/off, Curve on/off, Up, Down and Remove
The window. Everything on the right redraws the chart immediately: title and axis labels, the number and range of bins, native units or percentages on the Y axis, density curves and their smoothness, and per-dataset color, bars and curve.

The comparison of a biologically optimal corridor with a proposed alternative is the window's most powerful use, and it is the case Metric 4 of the Corridor Evaluation Tutorial works through. Load the same raster clipped to each corridor as two datasets, switch the Y axis to percentages so that corridors of different sizes can be read against each other, and the two distributions sit on one chart. Here the raster is distance to the nearest road: the alternative corridor keeps nearly all of its ground within 1.3 km of a road, while the optimal corridor's cells reach 3 km from one, a difference that a pair of mean values would understate and that the chart makes plain.

Histogram of distance to the nearest road as percentages: the alternative corridor in pink with 39 percent of its cells within 329 meters of a road and nearly all within 1,300 meters; the optimal corridor in green spread out to 3,000 meters
Distance to roads inside the optimal corridor (green) and the proposed alternative (pink), as percentages of each corridor's cells. Nearly all of the alternative lies within 1.3 km of a road; the optimum's cells reach 3 km from one.

Categorical data

The window also takes categorical data: a text field of a feature layer or table (owner type, vegetation class), or a classified raster such as land cover, using either the layer's unique-value symbology labels or any text column of its attribute table as the class names. The chart then shows one bar per class instead of one per bin, and classes are matched between datasets by name, so a land-cover raster clipped to two corridors lines up class for class. Bins, axis range and density curves do not apply to classes and are disabled while categorical data is loaded; percentages and area units still work. A categorical dataset cannot share a chart with a numeric one, and if the loaded datasets do not all carry the same classes the window says which classes each one lacks, since an empty slot is only a real finding when both were classified the same way.

Categorical histogram of NLCD land-cover class as percentages of two corridors: evergreen forest 31 percent of the optimal corridor and 10 percent of the alternative; grasslands 25 and 17 percent; scrub-shrub 41 and 67 percent; developed and agriculture under 1 and 3 percent; small shares of barren land and woody wetland in both
Land cover inside two corridors, one bar per class, from the Corridor Evaluation Tutorial. Long class names tilt automatically so they never overlap.

Colors and fonts

Select a dataset in the list and click Color... to choose its color from a colorblind-safe palette or the larger grid below it; the bars and the density curve follow. Rename... changes the legend text, Bars on/off and Curve on/off show or hide either element per dataset, and Up/Down set the drawing and legend order. Fonts... in the Chart group sets the face, size, bold and italic for the title, the axis labels, the legend and the axis numbers separately.

The Color dialog for a dataset: a colorblind-safe palette of eight colors on top, and a larger grid of more colors below
Color...: the colorblind-safe palette first, more colors below.
The Chart Fonts dialog: font, size in points, bold and italic for Title, Axis labels, Legend text and Axis numbers
Fonts...: four text roles, each with its own face, size and style.

Getting the chart out

Save Graph... writes the chart as a PNG image at 300 dpi or as an SVG vector file, exactly as drawn, for a report or a slide.

The exported chart as a standalone image: title, percent Y axis, two histograms with density curves, and the legend
Save Graph...: the chart as a PNG.

Add to Layout places the chart on an ArcGIS Pro layout as native graphic elements — every bar, curve, tick and label individually editable — together with the statistics report as a text element named Histogram Statistics. If a layout is the active view it goes there; otherwise the window asks which of the project's layouts to use, and if the project has none yet it points you to Insert ▸ New Layout.

A small Add to which layout dialog listing the project's layouts, with Layout5 selected, and Add to Layout and Cancel buttons
Asked only when the active view is not a layout.
A layout with the Habitat Suitability Comparison chart in the upper left, a Histogram Statistics text box beneath it listing the source, weight basis, total weight, mean, median, standard deviation, standard error, minimum, maximum, range and weighted sum of each dataset, and a map of the parcels and wildland blocks behind
Chart and statistics on a layout, beside the map they describe.

The remaining buttons cover the numbers rather than the picture: Copy Stats puts the statistics report on the clipboard as text; Export Tables... writes the general-statistics table and the per-bin table to a geodatabase, dBASE or CSV; and Save Datasets... / Load Datasets... keep a whole comparison — every dataset, its weighting, clip and color — in a small JSON file, so it can be reopened or rebuilt on new data without adding the datasets one by one.

Recommended citation

Jenness, J., D. Majka and P. Beier. 2026. Histograms and 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 by Jenness, Majka and Beier.

Licensing information

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