ESM: import * as projection from "@arcgis/core/geometry/projection.js";
CDN: const projection = await $arcgis.import("@arcgis/core/geometry/projection.js");
Object: @arcgis/core/geometry/projection
Since: ArcGIS Maps SDK for JavaScript 4.7
A client-side projection engine for converting geometries from one SpatialReference to another. When projecting geometries the starting spatial reference must be specified on the input geometry. You can specify a specific geographic (datum) transformation for the project operation, or accept the default transformation if one is needed.
Method Overview Method DetailsReturns the default geographic transformation used to convert the geometry from the input spatial reference to the output spatial reference. The default transformation is used when projecting geometries where the datum transformation is required but not specified in the geographicTransformation parameter.
Known Limitations
Parameters
The input spatial reference from which to project geometries. This is the spatial reference of the input geometries.
The spatial reference to which you are converting the geometries.
optionalAn extent used to determine the suitability of the returned transformation. The extent will be re-projected to the inSpatialReference if it has a different spatial reference.
Returns
Type Description GeographicTransformation | null | undefined Returns the default geographic transformation for the given parameters. If no transformation is required or there are no suitable transformations, thennull is returned.
Returns a list of all geographic transformations suitable to convert geometries from the input spatial reference to the specified output spatial reference. The list is ordered in descending order by suitability, with the most suitable being first in the list.
Known Limitations
Parameters
The spatial reference that the geometries are currently using.
The spatial reference to which you are converting the geometries to.
optionalAn extent used to determine the suitability of the returned transformations. The extent will be re-projected to the input spatial reference if necessary.
Returns
Type Description GeographicTransformation[] Returns an array containing the maximum number the suitable geographic transformations that can be used to convert geometries between input and output spatial references. The list will be empty if the provided extent lies out of the area of use for the input spatial reference.Example
const cs1 = new SpatialReference({
wkid: 4272 //PE_GCS_ED_1950
});
const cs2 = new SpatialReference({
wkid: 4167
});
const extent = new Extent({
xmin: -186.0,
ymin: -42.0,
xmax: -179.0,
ymax: -38.0
});
const geogtrans = projection.getTransformations(cs1, cs2, extent);
geogtrans.forEach(function(geogtran, index) {
geogtran.steps.forEach(function(step, index) {
console.log("step wkid: ", step.wkid);
});
}); isLoaded(){Boolean}
Indicates if all dependencies of this module have been loaded.
Returns
Type Description Boolean Returnstrue if this module's dependencies have been loaded.
load(){Promise}
Loads this module's dependencies. This method must be called before projecting geometries.
Returns
Type Description Promise Resolves when the dependencies have been loaded.Example
projection.load().then(function() {
// the projection module is loaded. Geometries can be re-projected.
// projects each polygon in the array
// project() will use the spatial reference of the first geometry in the array
// as an input spatial reference. It will use the default transformation
// if one is required when converting from input spatial reference
// to the output spatial reference
let outSpatialReference = new SpatialReference({
wkid: 53008 //Sphere_Sinusoidal projection
});
polygonGraphics.forEach(function(graphic) {
graphic.geometry = projection.project(graphic.geometry, outSpatialReference);
});
});Projects a geometry or an array of geometries to the specified output spatial reference. A default geographic transformation is used if not explicitly provided, but required. Use the getTransformation() method to find out which transformation is used by default for the given input and output spatial references.
Note that you must load this module before attempting to project geometries.
Known Limitations
This method uses the spatial reference of the first geometry as an input spatial reference. Therefore all geometries in the array must have the same spatial reference.
Returns
Type Description GeometryUnion | GeometryUnion[] The result will be an array if an array of geometries is used as input. It will be a single geometry if a single geometry used as input.Examples
// projects each polygon in the array
// project() will use the spatial reference of the first geometry in the array
// as an input spatial reference. It will use the default transformation
// if one is required when converting from input spatial reference
// to the output spatial reference
let outSpatialReference = new SpatialReference({
wkid: 53008 //Sphere_Sinusoidal projection
});
polygonGraphics.forEach(function(graphic) {
graphic.geometry = projection.project(graphic.geometry, outSpatialReference);
});let outSpatialReference = {
wkid: 54044
};
// projects an array of points
let projectedPoints = projection.project(wgsPoints, outSpatialReference);
projectedPoints.forEach(function(point) {
console.log(point.x, point.y);
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