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ArcGIS Runtime SDK for .NET

Viewshed for camera

This code sample is available for these platforms:
View Sample on GitHub

Analyze the viewshed for a camera. A viewshed shows the visible and obstructed areas from an observer's vantage point.

screenshot

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. Click the 'Viewshed from here' button to update the viewshed to the current camera position.

How it works

  1. Get the current camera from the scene with SceneView.getCurrentViewpointCamera().
  2. Create a LocationViewshed, passing in the Camera and a min/max distance.
  3. Update the viewshed from a camera.

Relevant API

  • AnalysisOverlay
  • Scene
  • ArcGISSceneLayer
  • ArcGISTiledElevationSource
  • Camera
  • LocationViewshed
  • SceneView

About the data

The scene shows a Brest, France building layer with a local elevation source.

Tags

3D, AnalysisOverlay, LocationViewshed, Scene, viewshed, visibility analysis

Sample Code

<UserControl
    x:Class="ArcGISRuntime.UWP.Samples.ViewshedCamera.ViewshedCamera"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:esriUI="using:Esri.ArcGISRuntime.UI.Controls">
    <Grid>
        <esriUI:SceneView x:Name="MySceneView" />
        <Border Style="{StaticResource BorderStyle}">
            <Button Content="Viewshed from here"
                    HorizontalAlignment="Stretch"
                    Click="UpdateObserverWithCamera" />
        </Border>
    </Grid>
</UserControl>
// Copyright 2017 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;
using System;

namespace ArcGISRuntime.UWP.Samples.ViewshedCamera
{
    [ArcGISRuntime.Samples.Shared.Attributes.Sample(
        "Viewshed for camera",
        "Analysis",
        "This sample demonstrates how to create a `LocationViewshed` to display interactive viewshed results in the scene view. The viewshed observer is defined by the scene view camera to evaluate visible and obstructed areas of the scene from that location.",
        "", "Featured")]
    public sealed partial class ViewshedCamera
    {
        // URL for a scene service of buildings in Brest, France
        private string _buildingsServiceUrl = @"https://tiles.arcgis.com/tiles/P3ePLMYs2RVChkJx/arcgis/rest/services/Buildings_Brest/SceneServer/layers/0";

        // URL for an image service to use as an elevation source
        private string _elevationSourceUrl = @"https://scene.arcgis.com/arcgis/rest/services/BREST_DTM_1M/ImageServer";

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

        public ViewshedCamera()
        {
            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(Basemap.CreateImagery());

            // Create a scene layer to show buildings in the Scene
            ArcGISSceneLayer buildingsLayer = new ArcGISSceneLayer(new Uri(_buildingsServiceUrl));
            myScene.OperationalLayers.Add(buildingsLayer);

            // 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 castle in Brest
            Camera observerCamera = new Camera(new MapPoint(-4.49492, 48.3808, 48.2511, SpatialReferences.Wgs84), 344.488, 74.1212, 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);
        }

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