KBE3D / KBCore / turf / standardDeviationalEllipse

函数: standardDeviationalEllipse()

standardDeviationalEllipse(points: FeatureCollection<Point>, options?: { properties?: GeoJsonProperties; weight?: string; steps?: number; }): StandardDeviationalEllipse

Function

Takes a collection of features and returns a standard deviational ellipse, also known as a “directional distribution.” The standard deviational ellipse aims to show the direction and the distribution of a dataset by drawing an ellipse that contains about one standard deviation’s worth (~ 70%) of the data.

This module mirrors the functionality of Distribution

in ArcGIS and the Standard Deviational Ellipse Plugin

Bibliography

• Robert S. Yuill, “The Standard Deviational Ellipse; An Updated Tool for Spatial Description,” Geografiska Annaler 53, no. 1 (1971): 28–39, doi:https://doi.org/10.2307/490885|10.2307/490885

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• Paul Hanly Furfey, “A Note on Lefever’s “Standard Deviational Ellipse,” American Journal of Sociology 33, no. 1 (1927): 94—98, doi:https://doi.org/10.1086/214336|10.1086/214336

.

参数

points

FeatureCollection<Point>

GeoJSON points

options?

Optional parameters

properties?

GeoJsonProperties

properties to pass to the resulting ellipse

weight?

string

the property name used to weight the center

steps?

number

number of steps for the polygon

返回

StandardDeviationalEllipse

an elliptical Polygon that includes approximately 1 SD of the dataset within it.

示例

const bbox = [-74, 40.72, -73.98, 40.74];
const points = turf.randomPoint(400, {bbox: bbox});
const sdEllipse = turf.standardDeviationalEllipse(points);

//addToMap
const addToMap = [points, sdEllipse];