hausdorffDistance

Computes the discrete Hausdorff distance between geometry a and geometry b. The Hausdorff distance is a measure of similarity: it is the greatest distance between any point in a and the closest point in b.

The discrete distance is an approximation of this metric: only vertices are considered. The parameter options.densify makes this approximation less coarse by splitting the line segments between vertices before computing the distance.

Parameters

Name	Type	Description
a	Geometry	First geometry
b	Geometry	Second geometry
options?	object	Optional options object
options.densify?	number	Optional fraction by which densify each line segment. Each segment will be split into a number of equal-length subsegments, whose fraction of the total length is closest to the given fraction. Value of 0.25 means that each segment will be split into four equal length subsegments. The closer to 0 the better the approximation of the distance.

Returns

number

Approximation of Hausdorff distance between geometries

Throws

• GEOSError on unsupported geometry types (curved)
• GEOSError when either geometry is empty
• GEOSError when options.densify is not in the range (0.0, 1.0]

See also

• frechetDistance

Examples

const a = lineString([ [ 0, 0 ], [ 100, 0 ], [ 10, 100 ], [ 10, 100 ] ]);
const b = lineString([ [ 0, 100 ], [ 0, 10 ], [ 80, 10 ] ]);
const ab_hDist = hausdorffDistance(a, b); // 22.360679774997898 - approximation is not close
const ab_hDist_d = hausdorffDistance(a, b, { densify: 0.001 }); // 47.89

const a = lineString([ [ 0, 0 ], [ 100, 0 ], [ 10, 100 ], [ 10, 100 ] ]); const b = lineString([ [ 0, 100 ], [ 0, 10 ], [ 80, 10 ] ]); const ab_hDist = hausdorffDistance(a, b); // 22.360679774997898 - approximation is not close const ab_hDist_d = hausdorffDistance(a, b, { densify: 0.001 }); // 47.89