distance

Computes the Cartesian distance between geometry a and geometry b.

Distance is in input geometry units.

Parameters

Name	Type	Description
a	Geometry | Prepared<Geometry>	First geometry
b	Geometry	Second geometry

Returns

number

The distance between geometries

Throws

• GEOSError on unsupported geometry types (curved)
• GEOSError when either geometry is empty

See also

• distanceWithin returns true when two geometries are within a given distance
• nearestPoints finds the nearest points of two geometries
• prepare improves performance of repeated calls against a single geometry

Examples

distance between point and line

const a = point([ 0, 0 ]);
const b = lineString([ [ 0, 1 ], [ 1, 0 ] ]);
const ab_dist = distance(a, b); // 0.7071067811865476 = Math.sqrt(2) / 2

const a = point([ 0, 0 ]); const b = lineString([ [ 0, 1 ], [ 1, 0 ] ]); const ab_dist = distance(a, b); // 0.7071067811865476 = Math.sqrt(2) / 2

distance between line and polygon

const a = lineString([ [ -1, 1 ], [ 1, -1 ] ]);
const b = polygon([ [ [ 1, 1 ], [ 1, 2 ], [ 2, 1 ], [ 1, 1 ] ] ]);
const ab_dist = distance(a, b); // 1.4142135623730951 = Math.sqrt(2)

const a = lineString([ [ -1, 1 ], [ 1, -1 ] ]); const b = polygon([ [ [ 1, 1 ], [ 1, 2 ], [ 2, 1 ], [ 1, 1 ] ] ]); const ab_dist = distance(a, b); // 1.4142135623730951 = Math.sqrt(2)

distance between two polygons

const a = polygon([ [ [ 0, 0 ], [ 1, 0 ], [ 1, 1 ], [ 0, 1 ], [ 0, 0 ] ] ]);
const b = polygon([ [ [ 2, 2 ], [ 3, 2 ], [ 3, 3 ], [ 2, 2 ] ] ]);
const ab_dist = distance(a, b); // 1.4142135623730951 = Math.sqrt(2)

const a = polygon([ [ [ 0, 0 ], [ 1, 0 ], [ 1, 1 ], [ 0, 1 ], [ 0, 0 ] ] ]); const b = polygon([ [ [ 2, 2 ], [ 3, 2 ], [ 3, 3 ], [ 2, 2 ] ] ]); const ab_dist = distance(a, b); // 1.4142135623730951 = Math.sqrt(2)

to improve performance of repeated calls against a single geometry

const a = buffer(point([ 0, 0 ]), 10, { quadrantSegments: 1000 });
// `a` is a polygon with many vertices (4000 in this example)
prepare(a);
// preparation of geometry `a` will improve the performance of repeated
// `distance` calls, but only those where `a` is the first geometry
const r1 = distance(a, point([ 12, 0 ]));
const r2 = distance(a, point([ 12, 1 ]));
const r3 = distance(point([ 12, 2 ]), a); // no benefit from prepared geometry