Set map spatial reference

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Sample viewer app

Specify a map's spatial reference.

Image of map spatial reference

Use case

Choosing the correct spatial reference is important for ensuring accurate projection of data points to a map.

How to use the sample

Pan and zoom around the map. Observe how the map is displayed using the World Bonne spatial reference.

How it works

  1. Instantiate an AGSMap object using a spatial reference with AGSMap.init(spatialReference:).
  2. Instantiate an AGSArcGISMapImageLayer object and add it to the map's operationalLayers property.
  3. Set the map to an AGSMapView object.

The ArcGIS map image layer will now use the spatial reference set to the ArcGIS map (World Bonne (WKID: 54024)) and not its default spatial reference (WGS84 (WKID: 4326)).

Relevant API

  • AGSArcGISMapImageLayer
  • AGSMap
  • AGSMapView
  • AGSSpatialReference

Additional information

Operational layers will automatically project to this spatial reference when possible.

Tags

project, WKID

Sample Code

SetMapsSRViewController.swift
                                        
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// Copyright 2016 Esri.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//   http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

import UIKit
import ArcGIS

class SetMapsSRViewController: UIViewController {
    @IBOutlet private weak var mapView: AGSMapView!

    private var map: AGSMap!

    override func viewDidLoad() {
        super.viewDidLoad()

        // add the source code button item to the right of navigation bar
        (self.navigationItem.rightBarButtonItem as! SourceCodeBarButtonItem).filenames = ["SetMapsSRViewController"]

        // initialize the map, spatial reference as world bonne (54024) or goode (54052)
        self.map = AGSMap(spatialReference: AGSSpatialReference(wkid: 54024)!)

        // Adding a map image layer which can reproject itself to the map's spatial reference
        // Note: Some layer such as tiled layer cannot reproject and will fail to draw if their spatial
        // reference is not the same as the map's spatial reference
        self.map.operationalLayers.add(AGSArcGISMapImageLayer(url: URL(string: "https://sampleserver6.arcgisonline.com/arcgis/rest/services/SampleWorldCities/MapServer")!))

        // assing the map to the map view
        self.mapView.map = self.map
    }
}

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