centerMedian

描述

¥Description

Takes a FeatureCollection of points and calculates the median center, algorithimically.The median center is understood as the point that is requires the least total travel from all other points.

Turfjs has four different functions for calculating the center of a set of data.Each is useful depending on circumstance.

@turf/center finds the simple center of a dataset, by finding the midpoint between the extents of the data.That is, it divides in half the farthest east and farthest west point as well as the farthest north and farthest south.

@turf/center-of-mass imagines that the dataset is a sheet of paper.The center of mass is where the sheet would balance on a fingertip.

@turf/center-mean takes the averages of all the coordinates and produces a value that respects that.Unlike @turf/center, it is sensitive to clusters and outliers.It lands in the statistical middle of a dataset, not the geographical.It can also be weighted, meaning certain points are more important than others.

@turf/center-median takes the mean center and tries to find, iteratively, a new point that requires the least amount of travel from all the points in the dataset.It is not as sensitive to outliers as @turf/center-mean, but it is attracted to clustered data.It, too, can be weighted.

参数

¥Parameters

名称	类型	描述
features	FeatureCollection<任意>	任意 GeoJSON 要素集合
options?	对象	可选参数（默认 ）
options.weight?	string	the property name used to weight the center
options.tolerance?	number	the difference in distance between candidate medians at which point the algorighim stops iterating.(默认 0.001)
options.counter?	number	how many attempts to find the median, should the tolerance be insufficient.(默认 10)

返回

¥Returns

特性<点> The median center of the collection

¥Feature<Point> The median center of the collection

示例

¥Examples

var points = turf.points([
  [0, 0],
  [1, 0],
  [0, 1],
  [5, 8],
]);
var medianCenter = turf.centerMedian(points);

安装

¥Installation

$ npm install @turf/center-median

import { centerMedian } from "@turf/center-median";
const result = centerMedian(...);

$ npm install @turf/turf

import * as turf from "@turf/turf";
const result = turf.centerMedian(...);