L.CRS

CRS

Abstract class that defines coordinate reference systems for projecting geographical points into pixel (screen) coordinates and back (and to coordinates in other units for WMS services). See spatial reference system. Leaflet defines the most usual CRSs by default. If you want to use a CRS not defined by default, take a look at the Proj4Leaflet plugin.

Methods

Method	Returns	Description
`latLngToPoint(<LatLng> latlng, <Number> zoom)`	`Point`	Projects geographical coordinates into pixel coordinates for a given zoom.
`pointToLatLng(<Point> point, <Number> zoom)`	`LatLng`	The inverse of `latLngToPoint`. Projects pixel coordinates on a given zoom into geographical coordinates.
`project(<LatLng> latlng)`	`Point`	Projects geographical coordinates into coordinates in units accepted for this CRS (e.g. meters for EPSG:3857, for passing it to WMS services).
`unproject(<Point> point)`	`LatLng`	Given a projected coordinate returns the corresponding LatLng. The inverse of `project`.
`scale(<Number> zoom)`	`Number`	Returns the scale used when transforming projected coordinates into pixel coordinates for a particular zoom. For example, it returns `256 * 2^zoom` for Mercator-based CRS.
`zoom(<Number> scale)`	`Number`	Inverse of `scale()`, returns the zoom level corresponding to a scale factor of `scale`.
`getProjectedBounds(<Number> zoom)`	`Bounds`	Returns the projection's bounds scaled and transformed for the provided `zoom`.
`distance(<LatLng> latlng1, <LatLng> latlng2)`	`Number`	Returns the distance between two geographical coordinates.
`wrapLatLng(<LatLng> latlng)`	`LatLng`	Returns a `LatLng` where lat and lng has been wrapped according to the CRS's `wrapLat` and `wrapLng` properties, if they are outside the CRS's bounds.

Properties

Property	Type	Description
`code`	`String`	Standard code name of the CRS passed into WMS services (e.g. `'EPSG:3857'`)
`wrapLng`	`Number[]`	An array of two numbers defining whether the longitude (horizontal) coordinate axis wraps around a given range and how. Defaults to `[-180, 180]` in most geographical CRSs. If `undefined`, the longitude axis does not wrap around.
`wrapLat`	`Number[]`	Like `wrapLng`, but for the latitude (vertical) axis.
`infinite`	`Boolean`	If true, the coordinate space will be unbounded (infinite in both axes)

Defined CRSs

CRS	Description
`L.CRS.EPSG3395`	Rarely used by some commercial tile providers. Uses Elliptical Mercator projection.
`L.CRS.EPSG3857`	The most common CRS for online maps, used by almost all free and commercial tile providers. Uses Spherical Mercator projection. Set in by default in Map's `crs` option.
`L.CRS.EPSG4326`	A common CRS among GIS enthusiasts. Uses simple Equirectangular projection.
`L.CRS.Earth`	Serves as the base for CRS that are global such that they cover the earth. Can only be used as the base for other CRS and cannot be used directly, since it does not have a `code`, `projection` or `transformation`. `distance()` returns meters.
`L.CRS.Simple`	A simple CRS that maps longitude and latitude into `x` and `y` directly. May be used for maps of flat surfaces (e.g. game maps). Note that the `y` axis should still be inverted (going from bottom to top). `distance()` returns simple euclidean distance.

v1.1.0