Coordinate

Coordinate represents a coordinate point, e.g. a geographic point (longitude, latitude) or a projected coordinate. It is the base data structure for maptalks coordinate conversions, extending Position (the common parent of Point and Coordinate).

import { Coordinate } from "maptalks";

const coord = new Coordinate(0, 0);
const coord2 = new Coordinate([121.47, 31.23]);
const coord3 = new Coordinate({ x: 0, y: 0 });

Constructor

new Coordinate(x, y, z?)
new Coordinate([x, y, z])
new Coordinate({ x, y, z })
new Coordinate(coordinate)

Parameters:

• x Number x coordinate value.
• y Number y coordinate value.
• z Number z value (optional; a plain property not used in operations).

Array [x, y], JSON object {x, y}, and another Coordinate are also accepted.

Throws if x/y are NaN.

Member Methods

Value & conversion

• toArray(): number[] — convert to an array [x, y] ([x, y, z] if z exists)
• toJSON(): { x, y, z? } — convert to a JSON object
• toFixed(n): Coordinate — round to n decimals
• copy(): Coordinate — return a copy

Arithmetic

• add(x, y?, z?): Coordinate — add another coordinate
• sub(x, y?, z?): Coordinate — subtract another coordinate
• substract(x, y?): Coordinate — alias of sub
• multi(ratio): Coordinate — multiply by a number
• div(n): Coordinate — divide by a number
• abs(): Coordinate — absolute value
• round(): Coordinate — round
• ceil(): Coordinate — ceil
• floor(): Coordinate — floor

Distance & comparison

• distanceTo(point): number — Euclidean distance to a point
• mag(): number — distance from the origin
• closeTo(p, delta?): boolean — whether within a delta
• equals(c): boolean — whether equal
• isZero(): boolean — whether zero

In-place set

• set(x, y, z?): this — set the coordinates (mutates and returns this)

Static Methods

• Coordinate.toNumberArrays(coordinates) — convert Coordinates to GeoJSON-style coordinate arrays (recursive)
• Coordinate.toCoordinates(coordinates) — convert GeoJSON-style coordinates to Coordinates (recursive)

const coord = new Coordinate(121.47, 31.23);
const arr = coord.toArray(); // [121.47, 31.23]
const dist = coord.distanceTo(new Coordinate(121.48, 31.24));

Coordinate is a pure data type with no event system. Coordinate projection conversion (lon/lat ↔ Web Mercator / pixel) is done by CRS/projection classes, not by Coordinate methods.