@mapbox/sphericalmercator
v2.0.1
Published
Transformations between the Web Mercator projection and Latitude Longitude coordinates
Downloads
438,331
Maintainers
Readme
sphericalmercator
Provides projection math for converting between mercator meters, screen pixels (of 256x256 or configurable-size tiles), and latitude/longitude. Compatible with nodejs packages and in-browser.
See also
- tilebelt provides ZXY tile math utilities in javascript
- mercantile provides similar utilities for projection and tile math in Python
Installation
npm install @mapbox/sphericalmercator
API
Some datatypes are assumed to be arrays: ll
is [lon, lat]
, xy
and px
are [x, y]
.
import { SphericalMercator } from '@mapbox/sphericalmercator';
// By default, precomputes up to z30
const merc = new SphericalMercator({
size: 256,
antimeridian: true
});
or, for CommonJS:
const { SphericalMercator } = require('@mapbox/sphericalmercator');
px(ll, zoom)
Convert lon, lat to screen pixel x, y from 0, 0 origin, at a certain zoom level. The inverse of ll
. If antimeridian: true
is passed on initialization of the SphericalMercator
object, this method will support converting longitude values up to 360°.
ll(px, zoom)
Convert screen pixel value to lon, lat, at a certain zoom level. The inverse of px
.
bbox(x, y, zoom, tmsStyle, srs)
Convert tile xyz value to bbox of the form [w, s, e, n]
x
{Number} x (longitude) number.y
{Number} y (latitude) number.zoom
{Number} zoom.tmsStyle
{Boolean} whether to compute using tms-style. (optional, default false)srs
{String} projection for resulting bbox (WGS84|900913). (optional, default WGS84)
Returns bbox array of values in form [w, s, e, n]
.
xyz(bbox, zoom, tmsStyle, srs)
Convert bbox to xyz bounds
bbox
{Number} bbox in the form[w, s, e, n]
.zoom
{Number} zoom.tmsStyle
{Boolean} whether to compute using tms-style. (optional, default false)srs
{String} projection of input bbox (WGS84|900913). (optional, default WGS84)
Returns {Object} XYZ bounds containing minX, maxX, minY, maxY properties.
convert(bbox, to)
Convert bbox from 900913 to WGS84 or vice versa
bbox
{Number} bbox in the form[w, s, e, n]
.to
{String} projection of resulting bbox (WGS84|900913). (optional, default WGS84)
Returns bbox array of values in form [w, s, e, n]
.
forward(ll)
Convert lon, lat values to mercator x, y
inverse(xy)
Convert mercator x, y values to lon, lat
Developing
npm ci # install
npm test # run tests
npm run format # format files with prettier