Show exploratory viewshed from camera in scene

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage x:Class="ArcGIS.Samples.ShowExploratoryViewshedFromCameraInScene.ShowExploratoryViewshedFromCameraInScene"
             xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             xmlns:esriUI="clr-namespace:Esri.ArcGISRuntime.Maui;assembly=Esri.ArcGISRuntime.Maui">
    <Grid>
        <esriUI:SceneView x:Name="MySceneView" />
        <Button x:Name="UpdateObserverButton"
                Margin="10"
                Clicked="UpdateObserverWithCamera"
                HorizontalOptions="End"
                Text="Viewshed from Here"
                VerticalOptions="Start" />
    </Grid>
</ContentPage>

// 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: 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.

using Esri.ArcGISRuntime.Geometry;
using Esri.ArcGISRuntime.Mapping;
using Esri.ArcGISRuntime.UI.GeoAnalysis;

namespace ArcGIS.Samples.ShowExploratoryViewshedFromCameraInScene
{
    [ArcGIS.Samples.Shared.Attributes.Sample(
        name: "Show exploratory viewshed from camera in scene",
        category: "Analysis",
        description: "Analyze the exploratory viewshed for a camera showing the visible and obstructed areas from an observer's vantage point.",
        instructions: "The sample will start with an exploratory viewshed created from the initial camera location, so only the visible (green) portion of the exploratory viewshed will be visible. Move around the scene to see the obstructed (red) portions. Tap the 'Update from Camera' button to update the exploratory viewshed to the current camera position.",
        tags: new[] { "3D", "exploratory viewshed", "integrated mesh", "scene", "visibility analysis" })]
    public partial class ShowExploratoryViewshedFromCameraInScene : ContentPage
    {
        // URL for a scene service of buildings in Girona.
        private string _gironaMeshUrl = "https://tiles.arcgis.com/tiles/z2tnIkrLQ2BRzr6P/arcgis/rest/services/Girona_Spain/SceneServer";

        // URL for an image service to use as an elevation source.
        private string _elevationSourceUrl = "https://elevation3d.arcgis.com/arcgis/rest/services/WorldElevation3D/Terrain3D/ImageServer";

        // Location viewshed analysis to show visible and obstructed areas from the camera
        private ExploratoryLocationViewshed _viewshedForCamera;

        public ShowExploratoryViewshedFromCameraInScene()
        {
            InitializeComponent();

            // Create the Scene, basemap, camera, and location viewshed analysis
            Initialize();
        }

        private void Initialize()
        {
            // Create a new Scene with an imagery basemap
            Scene myScene = new Scene(BasemapStyle.ArcGISImageryStandard);

            // Create a scene layer to show buildings in the Scene
            IntegratedMeshLayer meshLayer = new IntegratedMeshLayer(new Uri(_gironaMeshUrl));
            myScene.OperationalLayers.Add(meshLayer);

            // Create an elevation source for the Scene
            ArcGISTiledElevationSource elevationSrc = new ArcGISTiledElevationSource(new Uri(_elevationSourceUrl));
            myScene.BaseSurface.ElevationSources.Add(elevationSrc);

            // Add the Scene to the SceneView
            MySceneView.Scene = myScene;

            // Set the viewpoint with a new camera focused on the cathedral in Girona.
            Camera observerCamera = new Camera(new MapPoint(2.82691, 41.985, 124.987, SpatialReferences.Wgs84), 332.131, 82.4732, 0.0);
            MySceneView.SetViewpointCameraAsync(observerCamera);

            // Create an ExploratoryLocationViewshed analysis using the camera as the observer
            _viewshedForCamera = new ExploratoryLocationViewshed(observerCamera, 1, 1000);

            // Create an analysis overlay to contain the viewshed analysis results
            AnalysisOverlay viewshedOverlay = new AnalysisOverlay();

            // Add the location viewshed analysis to the analysis overlay, then add the overlay to the scene view
            viewshedOverlay.Analyses.Add(_viewshedForCamera);
            MySceneView.AnalysisOverlays.Add(viewshedOverlay);
        }

        private void UpdateObserverWithCamera(object sender, EventArgs e)
        {
            // Use the current camera to update the observer for the location viewshed analysis
            _viewshedForCamera.UpdateFromCamera(MySceneView.Camera);
        }
    }
}