d3-polygon ​

This module provides a few basic geometric operations for two-dimensional polygons. Each polygon is represented as an array of two-element arrays [​[ x0 , y0 ], [ x1 , y1 ], …], and may either be closed (wherein the first and last point are the same) or open (wherein they are not). Typically polygons are in counterclockwise order, assuming a coordinate system where the origin is in the top-left corner.

polygonArea( polygon ) ​

d3.polygonArea([[1, 1], [1.5, 0], [2, 1]]) // -0.5

Source · Returns the signed area of the specified polygon . If the vertices of the polygon are in counterclockwise order (assuming a coordinate system where the origin is in the top-left corner), the returned area is positive; otherwise it is negative, or zero.

polygonCentroid( polygon ) ​

d3.polygonCentroid([[1, 1], [1.5, 0], [2, 1]]) // [1.5, 0.6666666666666666]

Source · Returns the centroid of the specified polygon .

polygonHull( points ) ​

d3.polygonHull(points) // [[3.0872864263338777, -1.300100095019402], [1.6559368816733773, -2.5092525689499605], …]

d3.polygonContains([[1, 1], [1.5, 0], [2, 1]], [1.5, 0.667]) // true

d3.polygonLength([[1, 1], [1.5, 0], [2, 1]]) // 3.23606797749979