Module: ol/proj

Methods

module:ol/proj.addCoordinateTransforms(source, destination, forward, inverse)

proj.js, line 342

Registers coordinate transform functions to convert coordinates between the source projection and the destination projection. The forward and inverse functions convert coordinate pairs; this function converts these into the functions used internally which also handle extents and coordinate arrays.

Name	Type	Description
source	module:ol/proj/Projection~ProjectionLike	Source projection.
destination	module:ol/proj/Projection~ProjectionLike	Destination projection.
forward	function	The forward transform function (that is, from the source projection to the destination projection) that takes a module:ol/coordinate~Coordinate as argument and returns the transformed module:ol/coordinate~Coordinate.
inverse	function	The inverse transform function (that is, from the destination projection to the source projection) that takes a module:ol/coordinate~Coordinate as argument and returns the transformed module:ol/coordinate~Coordinate.

module:ol/proj.addEquivalentProjections(projections)

proj.js, line 229

Registers transformation functions that don't alter coordinates. Those allow to transform between projections with equal meaning.

Name	Type	Description
projections	Array.<module:ol/proj/Projection~Projection>	Projections.

module:ol/proj.addProjection(projection)

proj.js, line 135

Add a Projection object to the list of supported projections that can be looked up by their code.

Name	Type	Description
projection	module:ol/proj/Projection~Projection	Projection instance.

module:ol/proj.equivalent(projection1, projection2){boolean}

proj.js, line 395

Checks if two projections are the same, that is every coordinate in one projection does represent the same geographic point as the same coordinate in the other projection.

Name	Type	Description
projection1	module:ol/proj/Projection~Projection	Projection 1.
projection2	module:ol/proj/Projection~Projection	Projection 2.

Returns:

Equivalent.

module:ol/proj.fromLonLat(coordinate, opt_projection){module:ol/coordinate~Coordinate}

proj.js, line 359

Transforms a coordinate from longitude/latitude to a different projection.

Name	Type	Description
coordinate	module:ol/coordinate~Coordinate	Coordinate as longitude and latitude, i.e. an array with longitude as 1st and latitude as 2nd element.
projection	module:ol/proj/Projection~ProjectionLike	Target projection. The default is Web Mercator, i.e. 'EPSG:3857'.

Returns:

Coordinate projected to the target projection.

module:ol/proj.get(projectionLike){module:ol/proj/Projection~Projection}

proj.js, line 158

Fetches a Projection object for the code specified.

Name	Type	Description
projectionLike	module:ol/proj/Projection~ProjectionLike	Either a code string which is a combination of authority and identifier such as "EPSG:4326", or an existing projection object, or undefined.

Returns:

Projection object, or null if not in list.

module:ol/proj.getPointResolution(projection, resolution, point, opt_units){number}

proj.js, line 185

Get the resolution of the point in degrees or distance units. For projections with degrees as the unit this will simply return the provided resolution. For other projections the point resolution is by default estimated by transforming the 'point' pixel to EPSG:4326, measuring its width and height on the normal sphere, and taking the average of the width and height. A custom function can be provided for a specific projection, either by setting the getPointResolution option in the module:ol/proj/Projection~Projection constructor or by using module:ol/proj/Projection~Projection#setGetPointResolution to change an existing projection object.

Name	Type	Description
projection	module:ol/proj/Projection~ProjectionLike	The projection.
resolution	number	Nominal resolution in projection units.
point	module:ol/coordinate~Coordinate	Point to find adjusted resolution at.
units	module:ol/proj/Units	Units to get the point resolution in. Default is the projection's units.

Returns:

Point resolution.

module:ol/proj.getTransform(source, destination){module:ol/proj~TransformFunction}

proj.js, line 439

Given the projection-like objects, searches for a transformation function to convert a coordinates array from the source projection to the destination projection.

Name	Type	Description
source	module:ol/proj/Projection~ProjectionLike	Source.
destination	module:ol/proj/Projection~ProjectionLike	Destination.

Returns:

Transform function.

module:ol/proj.toLonLat(coordinate, opt_projection){module:ol/coordinate~Coordinate}

proj.js, line 374

Transforms a coordinate to longitude/latitude.

Name	Type	Description
coordinate	module:ol/coordinate~Coordinate	Projected coordinate.
projection	module:ol/proj/Projection~ProjectionLike	Projection of the coordinate. The default is Web Mercator, i.e. 'EPSG:3857'.

Returns:

Coordinate as longitude and latitude, i.e. an array with longitude as 1st and latitude as 2nd element.

module:ol/proj.transform(coordinate, source, destination){module:ol/coordinate~Coordinate}

proj.js, line 460

Transforms a coordinate from source projection to destination projection. This returns a new coordinate (and does not modify the original).

See module:ol/proj~transformExtent for extent transformation. See the transform method of module:ol/geom/Geometry~Geometry and its subclasses for geometry transforms.

Name	Type	Description
coordinate	module:ol/coordinate~Coordinate	Coordinate.
source	module:ol/proj/Projection~ProjectionLike	Source projection-like.
destination	module:ol/proj/Projection~ProjectionLike	Destination projection-like.

Returns:

Coordinate.

module:ol/proj.transformExtent(extent, source, destination){module:ol/extent~Extent}

proj.js, line 476

Transforms an extent from source projection to destination projection. This returns a new extent (and does not modify the original).

Name	Type	Description
extent	module:ol/extent~Extent	The extent to transform.
source	module:ol/proj/Projection~ProjectionLike	Source projection-like.
destination	module:ol/proj/Projection~ProjectionLike	Destination projection-like.

Returns:

The transformed extent.

Type Definitions

ProjectionLike{module:ol/proj/Projection~Projection} {string} {undefined}

A projection as module:ol/proj/Projection, SRS identifier string or undefined.

TransformFunction()

proj.js, line 75

A transform function accepts an array of input coordinate values, an optional output array, and an optional dimension (default should be 2). The function transforms the input coordinate values, populates the output array, and returns the output array.