Analyze the viewshed for a camera. A viewshed shows the visible and obstructed areas from an observer's vantage point.
Use case
A viewshed analysis is a type of visual analysis you can perform on a scene. The viewshed aims to answer the question 'What can I see from a given location?'. The output is an overlay with two different colors - one representing the visible areas (green) and the other representing the obstructed areas (red).
How to use the sample
The sample will start with a viewshed created from the initial camera location, so only the visible (green) portion of the viewshed will be visible. Move around the scene to see the obstructed (red) portions. Tap the button to update the viewshed to the current camera position.
How it works
Create a LocationViewshed, passing in a Camera and a min/max distance.
Update the viewshed using viewshed.UpdateFromCamera().
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// Copyright 2021 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 Android.App;
using Android.OS;
using Android.Views;
using Android.Widget;
using Esri.ArcGISRuntime.Geometry;
using Esri.ArcGISRuntime.Mapping;
using Esri.ArcGISRuntime.UI.Controls;
using Esri.ArcGISRuntime.UI.GeoAnalysis;
using System;
namespaceArcGISRuntime.Samples.ViewshedCamera{
[Activity(ConfigurationChanges = Android.Content.PM.ConfigChanges.Orientation | Android.Content.PM.ConfigChanges.ScreenSize)]
[ArcGISRuntime.Samples.Shared.Attributes.Sample(
name: "Viewshed for camera",
category: "Analysis",
description: "Analyze the viewshed for a camera. A viewshed shows the visible and obstructed areas from an observer's vantage point. ",
instructions: "The sample will start with a viewshed created from the initial camera location, so only the visible (green) portion of the viewshed will be visible. Move around the scene to see the obstructed (red) portions. Tap the button to update the viewshed to the current camera position.",
tags: new[] { "3D", "Scene", "integrated mesh", "viewshed", "visibility analysis" })]
publicclassViewshedCamera : Activity {
// Hold a reference to the scene viewprivate SceneView _mySceneView;
// URL for a scene service of buildings in Girona.privatestring _gironaMeshUrl = "https://tiles.arcgis.com/tiles/z2tnIkrLQ2BRzr6P/arcgis/rest/services/Girona_Spain/SceneServer";
// URL for an image service to use as an elevation source.privatestring _elevationSourceUrl = "https://elevation3d.arcgis.com/arcgis/rest/services/WorldElevation3D/Terrain3D/ImageServer";
// Location viewshed analysis to show visible and obstructed areas from the cameraprivate LocationViewshed _viewshedForCamera;
protectedoverridevoidOnCreate(Bundle bundle) {
base.OnCreate(bundle);
Title = "Viewshed camera";
// Create the UI CreateLayout();
// Create the Scene, basemap, camera, and location viewshed analysis Initialize();
}
privatevoidInitialize() {
// 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 a LocationViewshed analysis using the camera as the observer _viewshedForCamera = new LocationViewshed(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);
}
privatevoidUpdateObserverWithCamera(object sender, EventArgs e) {
// Use the current camera to update the observer for the location viewshed analysis _viewshedForCamera.UpdateFromCamera(_mySceneView.Camera);
}
privatevoidCreateLayout() {
// Create a new vertical layout for the app LinearLayout layout = new LinearLayout(this) { Orientation = Orientation.Vertical };
// Create a button to update the viewshed using the current camera Button updateViewshedButton = new Button(this)
{
Text = "Viewshed from here" };
updateViewshedButton.Click += UpdateObserverWithCamera;
// Add the button and scene view to the layout layout.AddView(updateViewshedButton);
_mySceneView = new SceneView(this);
layout.AddView(_mySceneView);
// Show the layout in the app SetContentView(layout);
}
protectedoverridevoidOnDestroy() {
base.OnDestroy();
// Remove the sceneview (_mySceneView.Parent as ViewGroup).RemoveView(_mySceneView);
_mySceneView.Dispose();
_mySceneView = null;
}
}
}