Methods
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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 sourcemodule:ol/proj/Projection~ProjectionLike Source projection.
destinationmodule:ol/proj/Projection~ProjectionLike Destination projection.
forwardfunction The forward transform function (that is, from the source projection to the destination projection) that takes a
module:ol/coordinate~Coordinateas argument and returns the transformedmodule:ol/coordinate~Coordinate.inversefunction The inverse transform function (that is, from the destination projection to the source projection) that takes a
module:ol/coordinate~Coordinateas argument and returns the transformedmodule:ol/coordinate~Coordinate. -
Registers transformation functions that don't alter coordinates. Those allow to transform between projections with equal meaning.
Name Type Description projectionsArray.<module:ol/proj/Projection~Projection> Projections.
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Add a Projection object to the list of supported projections that can be looked up by their code.
Name Type Description projectionmodule:ol/proj/Projection~Projection Projection instance.
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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 projection1module:ol/proj/Projection~Projection Projection 1.
projection2module:ol/proj/Projection~Projection Projection 2.
Returns:
Equivalent.
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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 coordinatemodule:ol/coordinate~Coordinate Coordinate as longitude and latitude, i.e. an array with longitude as 1st and latitude as 2nd element.
projectionmodule:ol/proj/Projection~ProjectionLike Target projection. The default is Web Mercator, i.e. 'EPSG:3857'.
Returns:
Coordinate projected to the target projection.
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Fetches a Projection object for the code specified.
Name Type Description projectionLikemodule: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.
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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
getPointResolutionoption in themodule:ol/proj/Projection~Projectionconstructor or by usingmodule:ol/proj/Projection~Projection#setGetPointResolutionto change an existing projection object.Name Type Description projectionmodule:ol/proj/Projection~ProjectionLike The projection.
resolutionnumber Nominal resolution in projection units.
pointmodule:ol/coordinate~Coordinate Point to find adjusted resolution at.
unitsmodule:ol/proj/Units Units to get the point resolution in. Default is the projection's units.
Returns:
Point resolution.
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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 sourcemodule:ol/proj/Projection~ProjectionLike Source.
destinationmodule:ol/proj/Projection~ProjectionLike Destination.
Returns:
Transform function.
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module:ol/proj.toLonLat(coordinate, opt_projection){module:ol/coordinate~Coordinate}
proj.js, line 374 -
Transforms a coordinate to longitude/latitude.
Name Type Description coordinatemodule:ol/coordinate~Coordinate Projected coordinate.
projectionmodule: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.
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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~transformExtentfor extent transformation. See the transform method ofmodule:ol/geom/Geometry~Geometryand its subclasses for geometry transforms.Name Type Description coordinatemodule:ol/coordinate~Coordinate Coordinate.
sourcemodule:ol/proj/Projection~ProjectionLike Source projection-like.
destinationmodule:ol/proj/Projection~ProjectionLike Destination projection-like.
Returns:
Coordinate.
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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 extentmodule:ol/extent~Extent The extent to transform.
sourcemodule:ol/proj/Projection~ProjectionLike Source projection-like.
destinationmodule:ol/proj/Projection~ProjectionLike Destination projection-like.
Returns:
The transformed extent.
Type Definitions
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A projection as
module:ol/proj/Projection, SRS identifier string or undefined. -
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.