Display a viewshed | ArcGIS Maps SDK for Swift

Learn how to perform and display a viewshed analysis in a 3D scene.

Figure : Overview of how to perform and display a viewshed analysis.

Viewshed analysis determines the visibility of terrain, buildings, and other 3D objects from an observer’s location within a scene (using a specified field of view). The result indicates which areas are visible and which are obstructed when viewed from the observer’s perspective.

In this tutorial, you will perform and display a viewshed analysis in a web scene. Your viewshed analysis will show visibility (visible or obstructed) and can be used to determine which hotspots in the Yosemite Valley are visible from a specified observer’s perspective.

Prerequisites

Before starting this tutorial:

You need an ArcGIS Location Platform or ArcGIS Online account.
Your system meets the system requirements.

Develop or Download

You have two options for completing this tutorial:

Option 1: Develop the code or
Option 2: Download the completed solution

Option 1: Develop the code

To start the tutorial, complete the Display a web scene tutorial. This creates a scene to display the trails, trailheads, and parks in the Santa Monica Mountains.

Open an Xcode project

Open the .xcodeproj project you created by completing the Display a web scene tutorial.
Continue with the following instructions to perform and display a viewshed analysis in a 3D scene.

Get the web scene item ID

You can use ArcGIS tools Tools, also known as developer tools, are ArcGIS software applications such as portal and ArcGIS Pro that developers can use to prepare content and data for custom applications they are building. Learn more to create and view web scenes A web scene is a scene stored as a JSON object that defines properties such as the basemap layer, data layers, layer styles, and pop-up styles. Its JSON structure is defined by the web scene specification. Learn more . Use the Scene Viewer Scene Viewer(™) is a browser-based mapping tool that can view, create, and save web scenes. Learn more to identify the web scene item ID An item ID is a unique identifier representing a single item stored, managed, and accessed in a portal, such as a web map, hosted layer, or file. Learn more . This item ID will be used later in the tutorial.

Go to the Yosemite Valley Hotspots web scene in the Scene Viewer in ArcGIS Online ArcGIS Online is a GIS mapping, analytics, data hosting, and content management software as a service (SaaS) product. It includes applications, tools, APIs, and location services for users and developers. It is subscription-based and requires an ArcGIS Online account. Learn more . This web scene displays terrain and hotspots in the Yosemite Valley.
Make a note of the item ID An item ID is a unique identifier representing a single item stored, managed, and accessed in a portal, such as a web map, hosted layer, or file. Learn more at the end of the browser’s URL. The item ID should be 7558ee942b2547019f66885c44d4f0b1.

Update the scene

In Xcode, in the Project Navigator, click ContentView.swift.

In the editor, modify the scene variable to create a Scene for the web scene. To do this, create a portal item providing the web scene’s item ID An item ID is a unique identifier representing a single item stored, managed, and accessed in a portal, such as a web map, hosted layer, or file. Learn more and a Portal referencing ArcGIS Online.

ContentView.swift

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    // The Yosemite Valley hotspots scene.
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    @State private var scene: ArcGIS.Scene = {
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        let portalItem = PortalItem(
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            portal: .arcGISOnline(connection: .anonymous),
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            id: Item.ID("7558ee942b2547019f66885c44d4f0b1")!
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        )
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        return Scene(item: portalItem)
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    }()

Create a viewshed analysis

Visual analyses are used to help you make sense of complex 3D data contained by a scene. Use a LocationViewshed to perform and display a viewshed A viewshed represents the locations visible from one or more specified points or lines. Learn more analysis using a 3D point to define the observer’s location.

Create a private class named Model of type ObservableObject and an accompanying State Object reference in the ContentView struct. See the programming patterns page for more information on how to manage states.

ContentView.swift


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// Copyright 2024 Esri
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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//   https://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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import SwiftUI
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import ArcGIS
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private class Model: ObservableObject {
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}
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struct ContentView: View {
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    // An ObservableObject containing the scene, graphics overlay, and analysis overlay.
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    @StateObject private var model = Model()
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    // The Yosemite Valley hotspots scene.
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    @State private var scene: ArcGIS.Scene = {
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        let portalItem = PortalItem(
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            portal: .arcGISOnline(connection: .anonymous),
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            id: Item.ID("7558ee942b2547019f66885c44d4f0b1")!
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        )
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        return Scene(item: portalItem)
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    }()
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}

Create an AnalysisOverlay named analysisOverlay to contain and display the viewshed analyses.

An analysis overlay is a container for Analysis objects. It is used with a scene view A scene view is a user interface that displays scene layers and graphics in 3D. It uses a camera to control the visible area of the scene and supports user interactions such as pan, zoom, tilt, and rotate. Learn more to display visual analyses on a scene A scene is a collection of layers that are displayed in 3D. It is typically composed of a basemap layer, data layers, and 3D data. Learn more . You can add more than one analysis overlay to a scene view. Analysis overlays are displayed on top of all other layers A layer is a reference to a collection of geographic data that is used to access and display data. The data for layers are typically provided by the basemap layer service and data services. Learn more and graphics overlays A graphics overlay is a client-side, temporary container of graphics to display on a map view or scene view. Learn more .
ContentView.swift
18 collapsed lines 1 // Copyright 2024 Esri 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); 4 // you may not use this file except in compliance with the License. 5 // You may obtain a copy of the License at 6 // 7 // https://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, 11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 // See the License for the specific language governing permissions and 13 // limitations under the License. 14 15 16 import SwiftUI 17 import ArcGIS 18 19 private class Model: ObservableObject { 20 21 // The analysis overlay to be added to the scene. 22 let analysisOverlay = AnalysisOverlay() 23 24 }

Create a private LocationViewshed named viewshed.

The viewshed analysis is added to a scene view A scene view is a user interface that displays scene layers and graphics in 3D. It uses a camera to control the visible area of the scene and supports user interactions such as pan, zoom, tilt, and rotate. Learn more using an analysis overlay. An analysis overlay is a container for analyses. It can be used to display visual analyses in a scene view. You can add more than one analysis overlay and they are displayed on top of all other layers A layer is a reference to a collection of geographic data that is used to access and display data. The data for layers are typically provided by the basemap layer service and data services. Learn more .

ContentView.swift


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// Copyright 2024 Esri
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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//   https://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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import SwiftUI
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import ArcGIS
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private class Model: ObservableObject {
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    // The analysis overlay to be added to the scene.
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    let analysisOverlay = AnalysisOverlay()
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    let viewshed: LocationViewshed
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}

Create a Double variable named maxDistance to track the viewshed’s maximum distance. Set the viewshed’s maxDistance property to the model’s maxDistance property in a didSet observer to update the maximum distance when needed.

ContentView.swift


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// Copyright 2024 Esri
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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//   https://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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import SwiftUI
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import ArcGIS
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private class Model: ObservableObject {
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    // The analysis overlay to be added to the scene.
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    let analysisOverlay = AnalysisOverlay()
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    let viewshed: LocationViewshed
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    var maxDistance: Double {
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        didSet {
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            viewshed.maxDistance = maxDistance
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        }
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    }
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}

In init(), initialize all of the properties, make the viewshed not visible upon launch, and add the viewshed to the analysis overlay.

ContentView.swift


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// Copyright 2024 Esri
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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//   https://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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import SwiftUI
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import ArcGIS
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private class Model: ObservableObject {
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    // The analysis overlay to be added to the scene.
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    let analysisOverlay = AnalysisOverlay()
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    let viewshed: LocationViewshed
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    var maxDistance: Double {
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        didSet {
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            viewshed.maxDistance = maxDistance
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        }
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    }
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    init() {
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        self.viewshed = LocationViewshed(
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            location: Point(latitude: 0, longitude: 0),
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            heading: 0,
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            pitch: 90,
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            horizontalAngle: 360,
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            verticalAngle: 180,
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            minDistance: 10,
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            maxDistance: 12_000
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        )
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        viewshed.isVisible = false
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        analysisOverlay.addAnalysis(viewshed)
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        maxDistance = viewshed.maxDistance!
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    }
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}

Define a private method named setViewshedLocation(point:) that receives a point as a parameter. This method is used to set the location of the viewshed and make it visible, if it is not visible already.

ContentView.swift


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// Copyright 2024 Esri
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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//   https://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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import SwiftUI
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import ArcGIS
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private class Model: ObservableObject {
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    // The analysis overlay to be added to the scene.
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    let analysisOverlay = AnalysisOverlay()
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    let viewshed: LocationViewshed
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    var maxDistance: Double {
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        didSet {
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            viewshed.maxDistance = maxDistance
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        }
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    }
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    init() {
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        self.viewshed = LocationViewshed(
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            location: Point(latitude: 0, longitude: 0),
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            heading: 0,
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            pitch: 90,
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            horizontalAngle: 360,
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            verticalAngle: 180,
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            minDistance: 10,
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            maxDistance: 12_000
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        )
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        viewshed.isVisible = false
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        analysisOverlay.addAnalysis(viewshed)
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        maxDistance = viewshed.maxDistance!
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    }
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    func setViewshedLocation(point: Point) {
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        viewshed.location = point
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        if !viewshed.isVisible {
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            viewshed.isVisible = true
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        }
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    }
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}

Define a private method named hideViewshed(). This method is used to hide the viewshed.

ContentView.swift


46 collapsed lines
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// Copyright 2024 Esri
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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//   https://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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import SwiftUI
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import ArcGIS
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private class Model: ObservableObject {
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    // The analysis overlay to be added to the scene.
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    let analysisOverlay = AnalysisOverlay()
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    let viewshed: LocationViewshed
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    var maxDistance: Double {
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        didSet {
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            viewshed.maxDistance = maxDistance
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        }
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    }
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    init() {
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        self.viewshed = LocationViewshed(
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            location: Point(latitude: 0, longitude: 0),
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            heading: 0,
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            pitch: 90,
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            horizontalAngle: 360,
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            verticalAngle: 180,
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            minDistance: 10,
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            maxDistance: 12_000
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        )
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        viewshed.isVisible = false
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        analysisOverlay.addAnalysis(viewshed)
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        maxDistance = viewshed.maxDistance!
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    }
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    func setViewshedLocation(point: Point) {
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        viewshed.location = point
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        if !viewshed.isVisible {
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            viewshed.isVisible = true
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        }
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    }
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    func hideViewshed() {
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        viewshed.isVisible = false
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    }
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}

Display the viewshed analysis with touch events

Touch events determine where to place the observer for the viewshed analysis. A user will long-press and drag to reveal and move the observer’s location.

The first step to displaying the analyses is to add the analysis overlay to the scene view. In the ContentView struct, modify the scene view to add the model’s analysis overlay.

ContentView.swift


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// Copyright 2024 Esri
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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//   https://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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import SwiftUI
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import ArcGIS
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private class Model: ObservableObject {
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    // The analysis overlay to be added to the scene.
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    let analysisOverlay = AnalysisOverlay()
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    let viewshed: LocationViewshed
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    var maxDistance: Double {
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        didSet {
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            viewshed.maxDistance = maxDistance
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        }
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    }
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    init() {
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        self.viewshed = LocationViewshed(
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            location: Point(latitude: 0, longitude: 0),
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            heading: 0,
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            pitch: 90,
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            horizontalAngle: 360,
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            verticalAngle: 180,
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            minDistance: 10,
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            maxDistance: 12_000
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        )
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        viewshed.isVisible = false
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        analysisOverlay.addAnalysis(viewshed)
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        maxDistance = viewshed.maxDistance!
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    }
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    func setViewshedLocation(point: Point) {
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        viewshed.location = point
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        if !viewshed.isVisible {
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            viewshed.isVisible = true
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        }
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    }
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    func hideViewshed() {
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        viewshed.isVisible = false
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    }
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}
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struct ContentView: View {
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    // An ObservableObject containing the scene, graphics overlay, and analysis overlay.
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    @StateObject private var model = Model()
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    // The Yosemite Valley hotspots scene.
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    @State private var scene: ArcGIS.Scene = {
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        let portalItem = PortalItem(
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            portal: .arcGISOnline(connection: .anonymous),
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            id: Item.ID("7558ee942b2547019f66885c44d4f0b1")!
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        )
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        return Scene(item: portalItem)
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    }()
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    var body: some View {
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        SceneView(scene: scene, analysisOverlays: [model.analysisOverlay])
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    }
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}

To add or move the viewshed analysis upon long press and drag, add the onLongPressGesture(perform:) method to the SceneView. In the closure, call the previously created setViewshedLocation(point:) method, passing in the scenePoint.

ContentView.swift


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// Copyright 2024 Esri
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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//   https://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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import SwiftUI
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import ArcGIS
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private class Model: ObservableObject {
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    // The analysis overlay to be added to the scene.
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    let analysisOverlay = AnalysisOverlay()
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    let viewshed: LocationViewshed
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    var maxDistance: Double {
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        didSet {
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            viewshed.maxDistance = maxDistance
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        }
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    }
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    init() {
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        self.viewshed = LocationViewshed(
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            location: Point(latitude: 0, longitude: 0),
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            heading: 0,
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            pitch: 90,
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            horizontalAngle: 360,
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            verticalAngle: 180,
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            minDistance: 10,
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            maxDistance: 12_000
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        )
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        viewshed.isVisible = false
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        analysisOverlay.addAnalysis(viewshed)
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        maxDistance = viewshed.maxDistance!
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    }
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    func setViewshedLocation(point: Point) {
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        viewshed.location = point
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        if !viewshed.isVisible {
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            viewshed.isVisible = true
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        }
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    }
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    func hideViewshed() {
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        viewshed.isVisible = false
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    }
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}
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struct ContentView: View {
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    // An ObservableObject containing the scene, graphics overlay, and analysis overlay.
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    @StateObject private var model = Model()
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    // The Yosemite Valley hotspots scene.
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    @State private var scene: ArcGIS.Scene = {
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        let portalItem = PortalItem(
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            portal: .arcGISOnline(connection: .anonymous),
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            id: Item.ID("7558ee942b2547019f66885c44d4f0b1")!
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        )
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        return Scene(item: portalItem)
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    }()
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    var body: some View {
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        SceneView(scene: scene, analysisOverlays: [model.analysisOverlay])
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            .onLongPressGesture { _, scenePoint in
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                guard let scenePoint = scenePoint else { return }
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                model.setViewshedLocation(point: scenePoint)
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            }
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    }
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}

Add a UI to control the viewshed analysis

To control the viewshed analysis, some UI elements are required.

Add a toolbar to the bottom of the scene view.

ContentView.swift


75 collapsed lines
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// Copyright 2024 Esri
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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//   https://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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import SwiftUI
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import ArcGIS
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private class Model: ObservableObject {
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    // The analysis overlay to be added to the scene.
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    let analysisOverlay = AnalysisOverlay()
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    let viewshed: LocationViewshed
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    var maxDistance: Double {
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        didSet {
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            viewshed.maxDistance = maxDistance
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        }
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    }
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    init() {
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        self.viewshed = LocationViewshed(
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            location: Point(latitude: 0, longitude: 0),
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            heading: 0,
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            pitch: 90,
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            horizontalAngle: 360,
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            verticalAngle: 180,
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            minDistance: 10,
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            maxDistance: 12_000
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        )
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        viewshed.isVisible = false
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        analysisOverlay.addAnalysis(viewshed)
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        maxDistance = viewshed.maxDistance!
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    }
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    func setViewshedLocation(point: Point) {
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        viewshed.location = point
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        if !viewshed.isVisible {
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            viewshed.isVisible = true
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        }
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    }
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    func hideViewshed() {
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        viewshed.isVisible = false
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    }
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}
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struct ContentView: View {
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    // An ObservableObject containing the scene, graphics overlay, and analysis overlay.
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    @StateObject private var model = Model()
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    // The Yosemite Valley hotspots scene.
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    @State private var scene: ArcGIS.Scene = {
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        let portalItem = PortalItem(
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            portal: .arcGISOnline(connection: .anonymous),
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            id: Item.ID("7558ee942b2547019f66885c44d4f0b1")!
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        )
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        return Scene(item: portalItem)
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    }()
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    var body: some View {
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        SceneView(scene: scene, analysisOverlays: [model.analysisOverlay])
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            .onLongPressGesture { _, scenePoint in
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                guard let scenePoint = scenePoint else { return }
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                model.setViewshedLocation(point: scenePoint)
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            }
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            .toolbar {
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                ToolbarItemGroup(placement: .bottomBar) {
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                }
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            }
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    }
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}

Add a Slider named slider to the toolbar with the model’s maxDistance property as its value and 10...12_000 as the range. The slider changes the viewshed’s maximum distance by expanding or contracting the size of the observer’s field of view. The maximumValue and minimumValue properties define the range of values the user can select to calculate the viewshed. You set an action on the slider using a selector for a method that will be added in a later step.

ContentView.swift


84 collapsed lines
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// Copyright 2024 Esri
2
//
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// Licensed under the Apache License, Version 2.0 (the "License");
4
// you may not use this file except in compliance with the License.
5
// You may obtain a copy of the License at
6
//
7
//   https://www.apache.org/licenses/LICENSE-2.0
8
//
9
// Unless required by applicable law or agreed to in writing, software
10
// distributed under the License is distributed on an "AS IS" BASIS,
11
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12
// See the License for the specific language governing permissions and
13
// limitations under the License.
14

15

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import SwiftUI
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import ArcGIS
18

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private class Model: ObservableObject {
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    // The analysis overlay to be added to the scene.
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    let analysisOverlay = AnalysisOverlay()
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    let viewshed: LocationViewshed
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    var maxDistance: Double {
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        didSet {
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            viewshed.maxDistance = maxDistance
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        }
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    }
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    init() {
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        self.viewshed = LocationViewshed(
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            location: Point(latitude: 0, longitude: 0),
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            heading: 0,
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            pitch: 90,
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            horizontalAngle: 360,
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            verticalAngle: 180,
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            minDistance: 10,
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            maxDistance: 12_000
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        )
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        viewshed.isVisible = false
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        analysisOverlay.addAnalysis(viewshed)
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        maxDistance = viewshed.maxDistance!
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    }
46

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    func setViewshedLocation(point: Point) {
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        viewshed.location = point
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        if !viewshed.isVisible {
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            viewshed.isVisible = true
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        }
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    }
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    func hideViewshed() {
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        viewshed.isVisible = false
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    }
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}
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struct ContentView: View {
61

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    // An ObservableObject containing the scene, graphics overlay, and analysis overlay.
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    @StateObject private var model = Model()
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    // The Yosemite Valley hotspots scene.
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    @State private var scene: ArcGIS.Scene = {
67

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        let portalItem = PortalItem(
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            portal: .arcGISOnline(connection: .anonymous),
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            id: Item.ID("7558ee942b2547019f66885c44d4f0b1")!
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        )
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        return Scene(item: portalItem)
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    }()
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    var body: some View {
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        SceneView(scene: scene, analysisOverlays: [model.analysisOverlay])
79

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            .onLongPressGesture { _, scenePoint in
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                guard let scenePoint = scenePoint else { return }
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                model.setViewshedLocation(point: scenePoint)
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            }
84

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            .toolbar {
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                ToolbarItemGroup(placement: .bottomBar) {
87

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                    Slider(value: $model.maxDistance, in: 10...12_000)
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                        .frame(width: 300)
90

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                }
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            }
4 collapsed lines
93

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    }
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}

Lastly, create a toolbar and add a “Clear” button to reset the analysis overlay. The “Clear” button calls the previously created hideViewshed() method. This will allow users a fresh start to make more analyses.

ContentView.swift


84 collapsed lines
1
// Copyright 2024 Esri
2
//
3
// Licensed under the Apache License, Version 2.0 (the "License");
4
// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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//   https://www.apache.org/licenses/LICENSE-2.0
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//
9
// Unless required by applicable law or agreed to in writing, software
10
// distributed under the License is distributed on an "AS IS" BASIS,
11
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12
// See the License for the specific language governing permissions and
13
// limitations under the License.
14

15

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import SwiftUI
17
import ArcGIS
18

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private class Model: ObservableObject {
20

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    // The analysis overlay to be added to the scene.
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    let analysisOverlay = AnalysisOverlay()
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    let viewshed: LocationViewshed
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    var maxDistance: Double {
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        didSet {
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            viewshed.maxDistance = maxDistance
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        }
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    }
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    init() {
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        self.viewshed = LocationViewshed(
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            location: Point(latitude: 0, longitude: 0),
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            heading: 0,
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            pitch: 90,
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            horizontalAngle: 360,
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            verticalAngle: 180,
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            minDistance: 10,
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            maxDistance: 12_000
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        )
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        viewshed.isVisible = false
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        analysisOverlay.addAnalysis(viewshed)
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        maxDistance = viewshed.maxDistance!
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    }
46

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    func setViewshedLocation(point: Point) {
48
        viewshed.location = point
49
        if !viewshed.isVisible {
50
            viewshed.isVisible = true
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        }
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    }
53

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    func hideViewshed() {
55
        viewshed.isVisible = false
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    }
57

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}
59

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struct ContentView: View {
61

62
    // An ObservableObject containing the scene, graphics overlay, and analysis overlay.
63
    @StateObject private var model = Model()
64

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    // The Yosemite Valley hotspots scene.
66
    @State private var scene: ArcGIS.Scene = {
67

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        let portalItem = PortalItem(
69
            portal: .arcGISOnline(connection: .anonymous),
70
            id: Item.ID("7558ee942b2547019f66885c44d4f0b1")!
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        )
72

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        return Scene(item: portalItem)
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    }()
75

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    var body: some View {
77

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        SceneView(scene: scene, analysisOverlays: [model.analysisOverlay])
79

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            .onLongPressGesture { _, scenePoint in
81
                guard let scenePoint = scenePoint else { return }
82
                model.setViewshedLocation(point: scenePoint)
83
            }
84

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            .toolbar {
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                ToolbarItemGroup(placement: .bottomBar) {
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                    Slider(value: $model.maxDistance, in: 10...12_000)
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                        .frame(width: 300)
90

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                    Spacer()
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                    Button("Clear") {
93
                        // Resets the line of sight.
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                        model.hideViewshed()
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                    }
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                }
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            }
4 collapsed lines
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    }
101

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}

Run the solution

Press Command + R to run the app.

If you are using the Xcode simulator your system must meet these minimum requirements: macOS 14 (Sonoma), Xcode 16, iOS 18. If you are using a physical device, then refer to the system requirements.

You should see a scene of hotspots in the Yosemite Valley. Long-press and drag to display and move a viewshed analysis to explore the visibility of terrain from various locations.

Alternatively, you can download the tutorial solution, as follows.

Option 2: Download the solution

Click the Download solution link under Solution and unzip the file to a location on your machine.
Open the .xcodeproj file in Xcode.

Since the downloaded solution does not contain authentication credentials, you must first set up authentication to create credentials, and then add the developer credentials to the solution.

Set up authentication

To access the secure ArcGIS location services ArcGIS Location Services, also referred to as Location Services, are services hosted by Esri that provide geospatial functionality for developing mapping applications. They include the ArcGIS Basemap Styles service, ArcGIS Static Basemap Tiles service, ArcGIS Places service, ArcGIS Geocoding service, ArcGIS Routing service, ArcGIS GeoEnrichment service, and ArcGIS Elevation service. An ArcGIS Location Platform or ArcGIS Online account is required to use the services. Learn more used in this tutorial, you must implement API key authentication API key authentication is a type of authentication that uses an API key to authenticate requests to ArcGIS services and secure portal items. Learn more or user authentication User authentication is a type of authentication that allows users with an ArcGIS account to sign into an application and allow it to access ArcGIS content, services, and resources on their behalf. The typical authorization protocol used is OAuth2.0. Learn more using an ArcGIS Location Platform An ArcGIS Location Platform account, formerly known as an ArcGIS Developer account, is an identity associated with an ArcGIS Location Platform subscription. Learn more or an ArcGIS Online An ArcGIS Online account, also known as an ArcGIS Organization account, is an identity associated with an ArcGIS Online subscription. It can be used to access ArcGIS tools and develop applications with ArcGIS location services for an organization. Learn more account.

You can implement API key authentication or user authentication in this tutorial. Compare the differences below:

API key authentication API key authentication is a type of authentication that uses an API key to authenticate requests to ArcGIS services and secure portal items. Learn more

Users are not required to sign in.
Requires creating an API key credential API key credentials are an item that contains the parameters used to create and manage long-lived access tokens for API key authentication. They are a type of developer credential. Learn more with the correct privileges.
API keys An API key is a long-lived access token created using API key credentials. They are valid for up to one year and are typically embedded directly into client applications. Learn more are long-lived access tokens.
Service usage is billed to the API key owner/developer.
Simplest authentication method to implement.
Recommended approach for new ArcGIS developers.

Learn more in API key authentication.

User authentication User authentication is a type of authentication that allows users with an ArcGIS account to sign into an application and allow it to access ArcGIS content, services, and resources on their behalf. The typical authorization protocol used is OAuth2.0. Learn more

Users are required to sign in with an ArcGIS account An ArcGIS account is an identity with a user type and set of privileges that can access specific ArcGIS products, tools, APIs, services, and resources. The main account types that can be used for development are an ArcGIS Location Platform account, ArcGIS Online account, and ArcGIS Enterprise account. ArcGIS Location Platform and ArcGIS Online accounts are also associated with a subscription. Learn more .
User accounts must have privilege Privileges are a set of permissions assigned to ArcGIS accounts, developer credentials, and applications that grant access to secure resources and functionality in ArcGIS. Learn more to access the ArcGIS services A service, also known as an ArcGIS service, is software that supports an ArcGIS REST API and provides geospatial functionality or data. A service can be hosted by Esri or in ArcGIS Enterprise. Learn more used in application.
Requires creating OAuth credentials OAuth credentials are an item that contains parameters required to implement user authentication or app authentication, including a client_id, client_secret, and redirect URIs. They are a type of developer credential. Learn more .
Application uses a redirect URL and client ID.
Service usage is billed to the organization of the user signed into the application.

Learn more in User authentication.

To complete this tutorial, click on the tab in the switcher below for your authentication type of choice, either API key authentication or User authentication.

Create a new API key access token An access token is an authorization string that provides access to secure ArcGIS content, data, and services. Its capabilities are determined by the privileges it supports. It is obtained by implementing API key authentication, User authentication, or App authentication. Learn more with privileges Privileges are a set of permissions assigned to ArcGIS accounts, developer credentials, and applications that grant access to secure resources and functionality in ArcGIS. Learn more to access the secure resources used in this tutorial.

Complete the Create an API key tutorial and create an API key with the following privilege(s) Privileges are a set of permissions assigned to ArcGIS accounts, developer credentials, and applications that grant access to secure resources and functionality in ArcGIS. Learn more :
- Privileges
  - Location services > Basemaps
Copy and paste the API key access token into a safe location. It will be used in a later step.

Create new OAuth credentials to access the secure resources used in this tutorial.

Complete the Create OAuth credentials for user authentication tutorial to obtain a Client ID and Redirect URL.

A Client ID uniquely identifies your app on the authenticating server. If the server cannot find an app with the provided Client ID, it will not proceed with authentication.
The Redirect URL (also referred to as a callback url) is used to identify a response from the authenticating server when the system returns control back to your app after an OAuth login. Since it does not necessarily represent a valid endpoint that a user could navigate to, the redirect URL can use a custom scheme, such as my-app://auth. It is important to make sure the redirect URL used in your app’s code matches a redirect URL configured on the authenticating server.
Copy and paste the Client ID and Redirect URL into a safe location. They will be used in a later step.

All users that access this application need account privileges Privileges are a set of permissions assigned to ArcGIS accounts, developer credentials, and applications that grant access to secure resources and functionality in ArcGIS. Learn more to access the ArcGIS Basemap Styles service The ArcGIS Basemap Styles service, also referred to as the Basemap Styles service, is a location service that provides basemap styles and data for the world. It returns styles as Mapbox styles and web maps, and data as vector tiles and/or map tiles. It supports all of the styles in the ArcGIS Basemap style and Open Basemap style family. An ArcGIS Location Platform or ArcGIS Online account is required to use the service. Learn more .

Set developer credentials in the solution

To allow your app users to access ArcGIS location services ArcGIS Location Services, also referred to as Location Services, are services hosted by Esri that provide geospatial functionality for developing mapping applications. They include the ArcGIS Basemap Styles service, ArcGIS Static Basemap Tiles service, ArcGIS Places service, ArcGIS Geocoding service, ArcGIS Routing service, ArcGIS GeoEnrichment service, and ArcGIS Elevation service. An ArcGIS Location Platform or ArcGIS Online account is required to use the services. Learn more , use the developer credentials that you created in the Set up authentication step to authenticate requests for resources.

Pass your API Key access token to the ArcGISEnvironment.

In the Project Navigator, click MainApp.swift.

Set the AuthenticationMode to .apiKey.

MainApp.swift

    // Change the `AuthenticationMode` to `.apiKey` if your application uses API key authentication.

    private var authenticationMode: AuthenticationMode { .apiKey }

Set the apiKey property with your API key access token.

MainApp.swift

31 collapsed lines
// Copyright 2022 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
//
//   https://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 SwiftUI
import ArcGIS
import ArcGISToolkit
@main

struct MainApp: App {

    // The authentication mode.
    private enum AuthenticationMode {
        case apiKey
        case user
    }

    // Change the `AuthenticationMode` to `.apiKey` if your application uses API key authentication.

    private var authenticationMode: AuthenticationMode { .apiKey }


    // Please enter an API key access token if your application uses API key authentication.

    private let apiKey = APIKey("<#YOUR-ACCESS-TOKEN#>")

43 collapsed lines

    // Setup an `Authenticator` with OAuth configuration if your application uses OAuth credentials.
    @ObservedObject var authenticator = Authenticator(
        oAuthUserConfigurations: [
            OAuthUserConfiguration(

                // Please enter OAuth credentials for user authentication.

                portalURL: URL(string: "<#YOUR-PORTAL-URL#>")!,
                clientID: "<#YOUR-CLIENT-ID#>",
                redirectURL: URL(string: "<#YOUR-REDIRECT-URL#>")!

            )
        ]
    )

    func setAuthentication() {
        switch authenticationMode {
        case .apiKey:
            ArcGISEnvironment.apiKey = apiKey
        case .user:
            ArcGISEnvironment.authenticationManager.arcGISAuthenticationChallengeHandler = authenticator
        }
    }

    init() {
        setAuthentication()
    }


    var body: some SwiftUI.Scene {

        WindowGroup {
            ContentView()

                .authenticator(authenticator)

                .ignoresSafeArea()

        }
    }

}

Best Practice: The access token is stored directly in the code as a convenience for this tutorial. Do not store credentials directly in source code in a production environment.

Use the Authenticator toolkit component to manage your OAuth credentials OAuth credentials are an item that contains parameters required to implement user authentication or app authentication, including a client_id, client_secret, and redirect URIs. They are a type of developer credential. Learn more and pass it to the ArcGISEnvironment.

In the Project Navigator, click MainApp.swift.

Set the AuthenticationMode to .user.

MainApp.swift

// Change the `AuthenticationMode` to `.user` if your application uses OAuth credentials.

private var authenticationMode: AuthenticationMode { .user }

Set your portalURL, clientID and redirectURL values.

MainApp.swift

36 collapsed lines
// Copyright 2022 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
//
//   https://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 SwiftUI
import ArcGIS
import ArcGISToolkit
@main

struct MainApp: App {

    // The authentication mode.
    private enum AuthenticationMode {
        case apiKey
        case user
    }

    // Change the `AuthenticationMode` to `.user` if your application uses OAuth credentials.

    private var authenticationMode: AuthenticationMode { .apiKey }


    // Please enter an API key access token if your application uses API key authentication.

    private let apiKey = APIKey("<#YOUR-ACCESS-TOKEN#>")


    // Setup an `Authenticator` with OAuth configuration if your application uses OAuth credentials.
    @ObservedObject var authenticator = Authenticator(
        oAuthUserConfigurations: [
            OAuthUserConfiguration(

                // Please enter OAuth credentials for user authentication.

                portalURL: URL(string: "<#YOUR-PORTAL-URL#>")!,
                clientID: "<#YOUR-CLIENT-ID#>",
                redirectURL: URL(string: "<#YOUR-REDIRECT-URL#>")!

            )
        ]
    )
28 collapsed lines

    func setAuthentication() {
        switch authenticationMode {
        case .apiKey:
            ArcGISEnvironment.apiKey = apiKey
        case .user:
            ArcGISEnvironment.authenticationManager.arcGISAuthenticationChallengeHandler = authenticator
        }
    }

    init() {
        setAuthentication()
    }


    var body: some SwiftUI.Scene {

        WindowGroup {
            ContentView()

                .authenticator(authenticator)

                .ignoresSafeArea()

        }
    }

}

Best Practice: The OAuth credentials are stored directly in the code as a convenience for this tutorial. Do not store credentials directly in source code in a production environment.

Run the solution

Press Command + R to run the app.

You should see a scene of hotspots in the Yosemite Valley. Long-press and drag to display and move a viewshed analysis to explore the visibility of terrain from various locations.

What’s next?

Learn how to use additional API features, ArcGIS location services, and ArcGIS tools in these tutorials:

Display a line of sight

Spatial and data analysisMake measurements TutorialsDisplay a line of sight