Viewshed (camera)

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Sample viewer app

This sample demonstrates how to calculate a Viewshed from a SceneView's current Camera Viewpoint.

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 'Update from Camera' button to update the viewshed to the current camera position.

How it works

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

Relevant API

  • AnalysisOverlay
  • ArcGISScene
  • ArcGISTiledElevationSource
  • Camera
  • IntegratedMeshLayer
  • LocationViewshed
  • SceneView

About the data

The scene shows an integrated mesh layer of Girona, Spain with the World Elevation source image service both hosted on ArcGIS Online.

Tags

3D, integrated mesh, Scene, viewshed, visibility analysis

Sample Code

ViewshedCamera.qml
                                                                                            
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// [WriteFile Name=ViewshedCamera, Category=Analysis]
// [Legal]
// 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.
// [Legal]

import QtQuick 2.6
import QtQuick.Controls 2.2
import Esri.ArcGISRuntime 100.11

Rectangle {
    id: rootRectangle
    clip: true
    width: 800
    height: 600

    SceneView {
        id: sceneView
        anchors.fill: parent

        Scene {
            id: scene
            Basemap {
                initStyle: Enums.BasemapStyleArcGISImageryStandard
            }

            // Set the Scene's Surface
            Surface {
                ArcGISTiledElevationSource {
                    url: "https://elevation3d.arcgis.com/arcgis/rest/services/WorldElevation3D/Terrain3D/ImageServer"
                }
            }

            // Add the Girona, Spain integrated mesh layer
            IntegratedMeshLayer {
                url: "https://tiles.arcgis.com/tiles/z2tnIkrLQ2BRzr6P/arcgis/rest/services/Girona_Spain/SceneServer"
            }

            // Set an initial viewpoint
            ViewpointCenter {
                Point {
                    id: centerPt
                    x: 2.82691
                    y: 41.98500
                    z: 124.987
                    spatialReference: Factory.SpatialReference.createWgs84()
                }
                targetScale: 1

                Camera {
                    id: camera
                    location: centerPt
                    heading: 332.131
                    pitch: 82.4732
                    roll: 0
                }
            }
        }

        // Declare an Analysis Overlay
        AnalysisOverlay {
            // Create the Location Viewshed
            LocationViewshed {
                id: locationViewshed
                minDistance: 1
                maxDistance: 1000
                frustumOutlineVisible: true
            }
        }
    }

    // calculate the viewshed on clicked
    Button {
        anchors {
            left: parent.left
            top: parent.top
            margins: 10
        }
        text: "Calculate Viewshed"
        onClicked: locationViewshed.updateFromCamera(sceneView.currentViewpointCamera);
    }
}

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