mapbox-gl
Version:
A WebGL interactive maps library
138 lines (126 loc) • 5.65 kB
JavaScript
// @flow
import { wrap } from '../util/util';
import LngLatBounds from './lng_lat_bounds';
/**
* A `LngLat` object represents a given longitude and latitude coordinate, measured in degrees.
*
* Mapbox GL uses longitude, latitude coordinate order (as opposed to latitude, longitude) to match GeoJSON.
*
* Note that any Mapbox GL method that accepts a `LngLat` object as an argument or option
* can also accept an `Array` of two numbers and will perform an implicit conversion.
* This flexible type is documented as {@link LngLatLike}.
*
* @param {number} lng Longitude, measured in degrees.
* @param {number} lat Latitude, measured in degrees.
* @example
* var ll = new mapboxgl.LngLat(-73.9749, 40.7736);
* @see [Get coordinates of the mouse pointer](https://www.mapbox.com/mapbox-gl-js/example/mouse-position/)
* @see [Display a popup](https://www.mapbox.com/mapbox-gl-js/example/popup/)
* @see [Highlight features within a bounding box](https://www.mapbox.com/mapbox-gl-js/example/using-box-queryrenderedfeatures/)
* @see [Create a timeline animation](https://www.mapbox.com/mapbox-gl-js/example/timeline-animation/)
*/
class LngLat {
lng: number;
lat: number;
constructor(lng: number, lat: number) {
if (isNaN(lng) || isNaN(lat)) {
throw new Error(`Invalid LngLat object: (${lng}, ${lat})`);
}
this.lng = +lng;
this.lat = +lat;
if (this.lat > 90 || this.lat < -90) {
throw new Error('Invalid LngLat latitude value: must be between -90 and 90');
}
}
/**
* Returns a new `LngLat` object whose longitude is wrapped to the range (-180, 180).
*
* @returns {LngLat} The wrapped `LngLat` object.
* @example
* var ll = new mapboxgl.LngLat(286.0251, 40.7736);
* var wrapped = ll.wrap();
* wrapped.lng; // = -73.9749
*/
wrap() {
return new LngLat(wrap(this.lng, -180, 180), this.lat);
}
/**
* Returns the coordinates represented as an array of two numbers.
*
* @returns {Array<number>} The coordinates represeted as an array of longitude and latitude.
* @example
* var ll = new mapboxgl.LngLat(-73.9749, 40.7736);
* ll.toArray(); // = [-73.9749, 40.7736]
*/
toArray() {
return [this.lng, this.lat];
}
/**
* Returns the coordinates represent as a string.
*
* @returns {string} The coordinates represented as a string of the format `'LngLat(lng, lat)'`.
* @example
* var ll = new mapboxgl.LngLat(-73.9749, 40.7736);
* ll.toString(); // = "LngLat(-73.9749, 40.7736)"
*/
toString() {
return `LngLat(${this.lng}, ${this.lat})`;
}
/**
* Returns a `LngLatBounds` from the coordinates extended by a given `radius`.
*
* @param {number} [radius=0] Distance in meters from the coordinates to extend the bounds.
* @returns {LngLatBounds} A new `LngLatBounds` object representing the coordinates extended by the `radius`.
* @example
* var ll = new mapboxgl.LngLat(-73.9749, 40.7736);
* ll.toBounds(100).toArray(); // = [[-73.97501862141328, 40.77351016847229], [-73.97478137858673, 40.77368983152771]]
*/
toBounds(radius?: number = 0) {
const earthCircumferenceInMetersAtEquator = 40075017;
const latAccuracy = 360 * radius / earthCircumferenceInMetersAtEquator,
lngAccuracy = latAccuracy / Math.cos((Math.PI / 180) * this.lat);
return new LngLatBounds(new LngLat(this.lng - lngAccuracy, this.lat - latAccuracy),
new LngLat(this.lng + lngAccuracy, this.lat + latAccuracy));
}
/**
* Converts an array of two numbers or an object with `lng` and `lat` or `lon` and `lat` properties
* to a `LngLat` object.
*
* If a `LngLat` object is passed in, the function returns it unchanged.
*
* @param {LngLatLike} input An array of two numbers or object to convert, or a `LngLat` object to return.
* @returns {LngLat} A new `LngLat` object, if a conversion occurred, or the original `LngLat` object.
* @example
* var arr = [-73.9749, 40.7736];
* var ll = mapboxgl.LngLat.convert(arr);
* ll; // = LngLat {lng: -73.9749, lat: 40.7736}
*/
static convert(input: LngLatLike): LngLat {
if (input instanceof LngLat) {
return input;
}
if (Array.isArray(input) && (input.length === 2 || input.length === 3)) {
return new LngLat(Number(input[0]), Number(input[1]));
}
if (!Array.isArray(input) && typeof input === 'object' && input !== null) {
return new LngLat(
// flow can't refine this to have one of lng or lat, so we have to cast to any
Number('lng' in input ? (input: any).lng : (input: any).lon),
Number(input.lat)
);
}
throw new Error("`LngLatLike` argument must be specified as a LngLat instance, an object {lng: <lng>, lat: <lat>}, an object {lon: <lng>, lat: <lat>}, or an array of [<lng>, <lat>]");
}
}
/**
* A {@link LngLat} object, an array of two numbers representing longitude and latitude,
* or an object with `lng` and `lat` or `lon` and `lat` properties.
*
* @typedef {LngLat | {lng: number, lat: number} | {lon: number, lat: number} | [number, number]} LngLatLike
* @example
* var v1 = new mapboxgl.LngLat(-122.420679, 37.772537);
* var v2 = [-122.420679, 37.772537];
* var v3 = {lon: -122.420679, lat: 37.772537};
*/
export type LngLatLike = LngLat | {lng: number, lat: number} | {lon: number, lat: number} | [number, number];
export default LngLat;