centerMedian

描述

¥Description

获取一个 FeatureCollection 点，并通过算法计算其中心点。中点是指从所有其他点到该点所需总行程最少的点。

¥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 有四种不同的函数用于计算一组数据的中心。每种方法都根据具体情况而定。

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

@turf/center 通过查找数据范围之间的中点来找到数据集的简单中心。也就是说，它将最东点和最西点以及最北点和最南点一分为二。

¥@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 将数据集想象成一张纸。重心是薄片在指尖上保持平衡的位置。

¥@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 取所有坐标的平均值，并生成一个与该平均值相符的值。与 @turf/center 不同，它对聚类和异常值敏感。它位于数据集的统计中间，而不是地理中间。它还可以加权，这意味着某些点比其他点更重要。

¥@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 取平均中心，并尝试迭代地从数据集中的所有点中找到一个需要最少行程的新点。它对异常值的敏感度不如 @turf/center-mean，但它对聚类数据有很强的吸引力。它也可以加权。

¥@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<any>	任意 GeoJSON 要素集合
options?	对象	可选参数（默认 {}）
options.weight?	string	用于加权中心的属性名称
options.tolerance?	number	候选中位数之间的距离差，算法在该点停止迭代。(默认 0.001)
options.counter?	number	如果容差不足，则尝试查找中值的次数。(默认 10)

返回

¥Returns

特性<点> 集合的中心点

¥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(...);