Module: ol/proj

Methods

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

proj.js, line 376

import {addCoordinateTransforms} from 'ol/proj';

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~ProjectionLike	Source projection.
destination	module:ol/proj~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. If the transform function can only transform less dimensions than the input coordinate, it is supposeed to return a coordinate with only the length it can transform. The other dimensions will be taken unchanged from the source.

module:ol/proj.addEquivalentProjections(projections)

proj.js, line 262

import {addEquivalentProjections} from 'ol/proj';

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 153

import {addProjection} from 'ol/proj';

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.clearUserProjection()

proj.js, line 567

import {clearUserProjection} from 'ol/proj';

Clear the user projection if set.

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

proj.js, line 441

import {equivalent} from 'ol/proj';

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 400

import {fromLonLat} from 'ol/proj';

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~ProjectionLike | undefined	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|null}

proj.js, line 174

import {get} from 'ol/proj';

Fetches a Projection object for the code specified.

Name	Type	Description
projectionLike	module:ol/proj~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 200

import {getPointResolution} from 'ol/proj';

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~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 | undefined	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 486

import {getTransform} from 'ol/proj';

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~ProjectionLike	Source.
destination	module:ol/proj~ProjectionLike	Destination.

Returns:

Transform function.

module:ol/proj.getUserProjection(){module:ol/proj/Projection~Projection|null}

proj.js, line 578

import {getUserProjection} from 'ol/proj';

Get the projection for coordinates supplied from and returned by API methods. Note that this method is not yet a part of the stable API. Support for user projections is not yet complete and should be considered experimental.

Returns:

The user projection (or null if not set).

module:ol/proj.setUserProjection(projection)

proj.js, line 559

import {setUserProjection} from 'ol/proj';

Set the projection for coordinates supplied from and returned by API methods. This includes all API methods except for those interacting with tile grids.

Name	Type	Description
projection	module:ol/proj~ProjectionLike	The user projection.

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

proj.js, line 418

import {toLonLat} from 'ol/proj';

Transforms a coordinate to longitude/latitude.

Name	Type	Description
coordinate	module:ol/coordinate~Coordinate	Projected coordinate.
projection	module:ol/proj~ProjectionLike | undefined	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 506

import {transform} from 'ol/proj';

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~ProjectionLike	Source projection-like.
destination	module:ol/proj~ProjectionLike	Destination projection-like.

Returns:

Coordinate.

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

proj.js, line 523

import {transformExtent} from 'ol/proj';

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~ProjectionLike	Source projection-like.
destination	module:ol/proj~ProjectionLike	Destination projection-like.
stops	number | undefined	Number of stops per side used for the transform. By default only the corners are used.

Returns:

The transformed extent.

module:ol/proj.useGeographic()

proj.js, line 587

import {useGeographic} from 'ol/proj';

Use geographic coordinates (WGS-84 datum) in API methods. This includes all API methods except for those interacting with tile grids.

Type Definitions

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

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

TransformFunction()

proj.js, line 86

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.