282 lines
8.4 KiB
JavaScript
282 lines
8.4 KiB
JavaScript
/**
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* @module ol/proj/Projection
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*/
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import {METERS_PER_UNIT} from './Units.js';
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/**
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* The function is called with a `number` view resolution and a
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* {@link module:ol/coordinate~Coordinate} as arguments, and returns the `number` resolution
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* in projection units at the passed coordinate.
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* @typedef {function(number, import("../coordinate.js").Coordinate):number} GetPointResolution
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* @api
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*/
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/**
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* @typedef {Object} Options
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* @property {string} code The SRS identifier code, e.g. `EPSG:4326`.
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* @property {import("./Units.js").Units} [units] Units. Required unless a
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* proj4 projection is defined for `code`.
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* @property {import("../extent.js").Extent} [extent] The validity extent for the SRS.
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* @property {string} [axisOrientation='enu'] The axis orientation as specified in Proj4.
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* @property {boolean} [global=false] Whether the projection is valid for the whole globe.
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* @property {number} [metersPerUnit] The meters per unit for the SRS.
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* If not provided, the `units` are used to get the meters per unit from the {@link METERS_PER_UNIT}
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* lookup table.
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* @property {import("../extent.js").Extent} [worldExtent] The world extent for the SRS.
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* @property {GetPointResolution} [getPointResolution]
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* Function to determine resolution at a point. The function is called with a
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* `number` view resolution and a {@link module:ol/coordinate~Coordinate} as arguments, and returns
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* the `number` resolution in projection units at the passed coordinate. If this is `undefined`,
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* the default {@link module:ol/proj.getPointResolution} function will be used.
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*/
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/**
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* @classdesc
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* In most cases, you should not need to create instances of this class.
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* Instead, where projection information is required, you can use a string
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* projection code or identifier (e.g. `EPSG:4326`) instead of a projection
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* instance.
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*
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* The library includes support for transforming coordinates between the following
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* projections:
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*
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* WGS 84 / Geographic - Using codes `EPSG:4326`, `CRS:84`, `urn:ogc:def:crs:EPSG:6.6:4326`,
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* `urn:ogc:def:crs:OGC:1.3:CRS84`, `urn:ogc:def:crs:OGC:2:84`, `http://www.opengis.net/gml/srs/epsg.xml#4326`,
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* or `urn:x-ogc:def:crs:EPSG:4326`
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* WGS 84 / Spherical Mercator - Using codes `EPSG:3857`, `EPSG:102100`, `EPSG:102113`, `EPSG:900913`,
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* `urn:ogc:def:crs:EPSG:6.18:3:3857`, or `http://www.opengis.net/gml/srs/epsg.xml#3857`
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* WGS 84 / UTM zones - Using codes `EPSG:32601` through `EPSG:32660` for northern zones
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* and `EPSG:32701` through `EPSG:32760` for southern zones. Note that the built-in UTM transforms
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* are lower accuracy (with errors on the order of 0.1 m) than those that you might get in a
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* library like [proj4js](https://github.com/proj4js/proj4js).
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*
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* For additional projection support, or to use higher accuracy transforms than the built-in ones, you can use
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* the [proj4js](https://github.com/proj4js/proj4js) library. With `proj4js`, after adding any new projection
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* definitions, call the {@link module:ol/proj/proj4.register} function.
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*
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* You can use the {@link module:ol/proj.get} function to retrieve a projection instance
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* for one of the registered projections.
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*
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* @api
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*/
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class Projection {
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/**
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* @param {Options} options Projection options.
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*/
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constructor(options) {
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/**
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* @private
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* @type {string}
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*/
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this.code_ = options.code;
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/**
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* Units of projected coordinates. When set to `TILE_PIXELS`, a
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* `this.extent_` and `this.worldExtent_` must be configured properly for each
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* tile.
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* @private
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* @type {import("./Units.js").Units}
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*/
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this.units_ = /** @type {import("./Units.js").Units} */ (options.units);
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/**
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* Validity extent of the projection in projected coordinates. For projections
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* with `TILE_PIXELS` units, this is the extent of the tile in
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* tile pixel space.
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* @private
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* @type {import("../extent.js").Extent}
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*/
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this.extent_ = options.extent !== undefined ? options.extent : null;
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/**
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* Extent of the world in EPSG:4326. For projections with
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* `TILE_PIXELS` units, this is the extent of the tile in
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* projected coordinate space.
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* @private
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* @type {import("../extent.js").Extent}
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*/
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this.worldExtent_ =
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options.worldExtent !== undefined ? options.worldExtent : null;
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/**
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* @private
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* @type {string}
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*/
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this.axisOrientation_ =
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options.axisOrientation !== undefined ? options.axisOrientation : 'enu';
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/**
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* @private
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* @type {boolean}
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*/
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this.global_ = options.global !== undefined ? options.global : false;
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/**
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* @private
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* @type {boolean}
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*/
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this.canWrapX_ = !!(this.global_ && this.extent_);
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/**
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* @private
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* @type {GetPointResolution|undefined}
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*/
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this.getPointResolutionFunc_ = options.getPointResolution;
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/**
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* @private
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* @type {import("../tilegrid/TileGrid.js").default}
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*/
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this.defaultTileGrid_ = null;
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/**
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* @private
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* @type {number|undefined}
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*/
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this.metersPerUnit_ = options.metersPerUnit;
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}
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/**
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* @return {boolean} The projection is suitable for wrapping the x-axis
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*/
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canWrapX() {
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return this.canWrapX_;
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}
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/**
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* Get the code for this projection, e.g. 'EPSG:4326'.
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* @return {string} Code.
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* @api
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*/
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getCode() {
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return this.code_;
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}
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/**
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* Get the validity extent for this projection.
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* @return {import("../extent.js").Extent} Extent.
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* @api
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*/
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getExtent() {
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return this.extent_;
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}
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/**
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* Get the units of this projection.
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* @return {import("./Units.js").Units} Units.
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* @api
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*/
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getUnits() {
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return this.units_;
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}
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/**
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* Get the amount of meters per unit of this projection. If the projection is
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* not configured with `metersPerUnit` or a units identifier, the return is
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* `undefined`.
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* @return {number|undefined} Meters.
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* @api
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*/
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getMetersPerUnit() {
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return this.metersPerUnit_ || METERS_PER_UNIT[this.units_];
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}
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/**
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* Get the world extent for this projection.
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* @return {import("../extent.js").Extent} Extent.
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* @api
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*/
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getWorldExtent() {
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return this.worldExtent_;
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}
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/**
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* Get the axis orientation of this projection.
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* Example values are:
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* enu - the default easting, northing, elevation.
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* neu - northing, easting, up - useful for "lat/long" geographic coordinates,
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* or south orientated transverse mercator.
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* wnu - westing, northing, up - some planetary coordinate systems have
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* "west positive" coordinate systems
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* @return {string} Axis orientation.
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* @api
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*/
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getAxisOrientation() {
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return this.axisOrientation_;
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}
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/**
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* Is this projection a global projection which spans the whole world?
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* @return {boolean} Whether the projection is global.
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* @api
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*/
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isGlobal() {
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return this.global_;
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}
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/**
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* Set if the projection is a global projection which spans the whole world
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* @param {boolean} global Whether the projection is global.
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* @api
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*/
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setGlobal(global) {
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this.global_ = global;
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this.canWrapX_ = !!(global && this.extent_);
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}
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/**
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* @return {import("../tilegrid/TileGrid.js").default} The default tile grid.
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*/
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getDefaultTileGrid() {
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return this.defaultTileGrid_;
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}
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/**
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* @param {import("../tilegrid/TileGrid.js").default} tileGrid The default tile grid.
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*/
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setDefaultTileGrid(tileGrid) {
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this.defaultTileGrid_ = tileGrid;
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}
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/**
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* Set the validity extent for this projection.
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* @param {import("../extent.js").Extent} extent Extent.
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* @api
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*/
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setExtent(extent) {
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this.extent_ = extent;
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this.canWrapX_ = !!(this.global_ && extent);
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}
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/**
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* Set the world extent for this projection.
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* @param {import("../extent.js").Extent} worldExtent World extent
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* [minlon, minlat, maxlon, maxlat].
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* @api
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*/
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setWorldExtent(worldExtent) {
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this.worldExtent_ = worldExtent;
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}
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/**
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* Set the getPointResolution function (see {@link module:ol/proj.getPointResolution}
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* for this projection.
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* @param {function(number, import("../coordinate.js").Coordinate):number} func Function
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* @api
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*/
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setGetPointResolution(func) {
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this.getPointResolutionFunc_ = func;
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}
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/**
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* Get the custom point resolution function for this projection (if set).
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* @return {GetPointResolution|undefined} The custom point
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* resolution function (if set).
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*/
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getPointResolutionFunc() {
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return this.getPointResolutionFunc_;
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}
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}
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export default Projection;
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