Surface placement

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Position graphics relative to a surface using different surface placement modes.

screenshot

Use case

Depending on the use case, data might be displayed at an absolute height (e.g. flight data recorded with altitude information), at a relative height to the terrain (e.g. transmission lines positioned relative to the ground), at a relative height to objects in the scene (e.g. extruded polygons, integrated mesh scene layer), or draped directly onto the terrain (e.g. location markers, area boundaries).

How to use the sample

The application loads a scene showing four points that use individual surface placement modes (Absolute, Relative, Relative to Scene, and either Draped Billboarded or Draped Flat). Use the toggle to change the draped mode and the slider to dynamically adjust the Z value of the graphics. Explore the scene by zooming in/out and by panning around to observe the effects of the surface placement rules.

How it works

  1. Create a GraphicsOverlay for each placement mode, setting LayerSceneProperties.surfacePlacement:

    • Absolute, position graphic using only its Z value.
    • Relative, position graphic using its Z value plus the elevation of the surface.
    • DrapedBillboarded, position graphic upright on the surface and always facing the camera, not using its z value.
    • DrapedFlat, position graphic flat on the surface, not using its z value.
    • RelativeToScene, position graphic using its Z value plus the altitude values of the scene.
  2. Add graphics to the graphics overlay, GraphicsOverlay.graphics.append(Graphic).
  3. Add each graphics overlay to the scene view by calling SceneView.graphicsOverlays.append(overlay).

Relevant API

  • Graphic
  • GraphicsOverlay
  • LayerSceneProperties.surfacePlacement
  • SceneProperties
  • Surface

About the data

The scene launches with a view of Brest, France. Four points are shown hovering with positions defined by each of the different surface placement modes.

Additional information

This sample uses an elevation service to add elevation/terrain to the scene. Graphics are positioned relative to that surface for the DrapedBillboarded, DrapedFlat, and Relative surface placement modes. It also uses a scene layer containing 3D models of buildings. Graphics are positioned relative to that scene layer for the RelativeToScene surface placement mode.

Tags

3D, absolute, altitude, draped, elevation, floating, relative, scenes, sea level, surface placement

Sample Code

Surface_Placement.qml
                                                                                                                                                                                                                                                                                                                                                                    
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// [WriteFile Name=Surface_Placement, Category=Scenes]
// [Legal]
// Copyright 2016 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 2.12
import QtQuick.Layouts 1.12
import Esri.ArcGISRuntime 100.12

Rectangle {
    width: 800
    height: 600

    // Add a scene view
    SceneView {
        id: sceneView
        anchors.fill: parent

        // Add a scene with the imagery basemap and world elevation surface
        Scene {
            Basemap {
                initStyle: Enums.BasemapStyleArcGISImageryStandard
            }

            Surface {
                ArcGISTiledElevationSource {
                    url: "https://elevation3d.arcgis.com/arcgis/rest/services/WorldElevation3D/Terrain3D/ImageServer"
                }
            }

            ArcGISSceneLayer {
                url: "https://tiles.arcgis.com/tiles/P3ePLMYs2RVChkJx/arcgis/rest/services/Buildings_Brest/SceneServer"
            }

            // set an initial viewpoint
            ViewpointCenter {
                Point {
                    id: initialViewpoint
                    x: -4.45968
                    y: 48.3889
                    z: 37.9922
                    spatialReference: SpatialReference { wkid: 4326 }
                }
                targetScale: 62.013264927081764

                Camera {
                    id: camera
                    location: initialViewpoint
                    heading: 329.91
                    pitch: 96.6632
                    roll: 0
                }
            }
        }

        // Graphics overlay with draped flat surface placement
        GraphicsOverlay {
            id: drapedFlatOverlay
            sceneProperties.surfacePlacement: Enums.SurfacePlacementDrapedFlat
            visible: false

            // Graphics will be draped on the surface of the scene and will appear flat
            Graphic {
                geometry: surfaceRelatedPoint

                SimpleMarkerSymbol {
                    color: "red"
                    style: Enums.SimpleMarkerSymbolStyleTriangle
                    size: 20
                }
            }

            Graphic {
                geometry: surfaceRelatedPoint

                TextSymbol {
                    size: 20
                    text: "DRAPED FLAT"
                    color: "blue"
                    horizontalAlignment: Enums.HorizontalAlignmentLeft
                    verticalAlignment: Enums.VerticalAlignmentMiddle
                    offsetX: 20
                }
            }
        }

        // Graphics overlay with draped billboard surface placement
        GraphicsOverlay {
            id: drapedBillboardedOverlay
            sceneProperties.surfacePlacement: Enums.SurfacePlacementDrapedBillboarded

            // Graphics will be draped on the surface of the scene and will always face the camera.
            Graphic {
                geometry: surfaceRelatedPoint

                SimpleMarkerSymbol {
                    color: "red"
                    style: Enums.SimpleMarkerSymbolStyleTriangle
                    size: 20
                }
            }

            Graphic {
                geometry: surfaceRelatedPoint

                TextSymbol {
                    size: 20
                    text: "DRAPED BILLBOARDED"
                    color: "blue"
                    horizontalAlignment: Enums.HorizontalAlignmentLeft
                    verticalAlignment: Enums.VerticalAlignmentMiddle
                    offsetX: 20
                }
            }
        }

        // Graphics overlay with relative surface placement
        GraphicsOverlay {
            id: relativeOverlay
            sceneProperties.surfacePlacement: Enums.SurfacePlacementRelative

            // Graphics will be placed at z value relative to the surface
            Graphic {
                geometry: surfaceRelatedPoint

                SimpleMarkerSymbol {
                    color: "red"
                    style: Enums.SimpleMarkerSymbolStyleTriangle
                    size: 20
                }
            }

            Graphic {
                geometry: surfaceRelatedPoint

                TextSymbol {
                    size: 20
                    text: "RELATIVE"
                    color: "blue"
                    horizontalAlignment: Enums.HorizontalAlignmentLeft
                    verticalAlignment: Enums.VerticalAlignmentMiddle
                    offsetX: 20
                }
            }
        }

        // Graphics overlay with absolute surface placement
        GraphicsOverlay {
            id: absoluteOverlay
            sceneProperties.surfacePlacement: Enums.SurfacePlacementAbsolute

            // Graphics will be placed at absolute z value
            Graphic {
                geometry: surfaceRelatedPoint

                SimpleMarkerSymbol {
                    color: "red"
                    style: Enums.SimpleMarkerSymbolStyleTriangle
                    size: 20
                }
            }

            Graphic {
                geometry: surfaceRelatedPoint

                TextSymbol {
                    size: 20
                    text: "ABSOLUTE"
                    color: "blue"
                    horizontalAlignment: Enums.HorizontalAlignmentLeft
                    verticalAlignment: Enums.VerticalAlignmentMiddle
                    offsetX: 20
                }
            }
        }

        GraphicsOverlay {
            id: relToScene
            sceneProperties.surfacePlacement: Enums.SurfacePlacementRelativeToScene

            // Graphics will be placed at absolute z value
            Graphic {
                geometry: sceneRelatedPoint

                SimpleMarkerSymbol {
                    color: "red"
                    style: Enums.SimpleMarkerSymbolStyleTriangle
                    size: 20
                }
            }

            Graphic {
                geometry: sceneRelatedPoint

                TextSymbol {
                    size: 20
                    text: "RELATIVE TO SCENE"
                    color: "blue"
                    horizontalAlignment: Enums.HorizontalAlignmentRight
                    verticalAlignment: Enums.VerticalAlignmentMiddle
                    offsetX: -20
                }
            }
        }
    }

    Rectangle {
        anchors {
            top: parent.top
            left: parent.left
            margins: 3
        }
        width: childrenRect.width
        height: childrenRect.height
        color: "#000000"
        opacity: .8
        radius: 5

        ColumnLayout {
            Text {
                Layout.alignment: Qt.AlignHCenter
                Layout.margins: 2
                text: qsTr("Draped mode")
                color: "white"
            }

            Switch {
                id: surfacePlacementMode
                Layout.alignment: Qt.AlignHCenter
                Layout.margins: 2

                onCheckedChanged: {
                    drapedFlatOverlay.visible = !drapedFlatOverlay.visible;
                    drapedBillboardedOverlay.visible = !drapedBillboardedOverlay.visible;
                }
            }
        }
    }

    Rectangle {
        anchors {
            top: parent.top
            right: parent.right
            margins: 5
        }
        width: childrenRect.width
        height: childrenRect.height
        color: "#000000"
        opacity: .8
        radius: 5

        MouseArea {
            anchors.fill: parent
            onClicked: mouse.accepted = true
            onWheel: wheel.accepted = true
        }

        ColumnLayout {
            Text {
                id: zValueSliderLabel
                text: qsTr("Z-Value")
                color: "white"
                Layout.margins: 2
                Layout.alignment: Qt.AlignHCenter
            }

            Slider {
                id: zValueSlider
                from: 0
                to: 140
                value: 70
                Layout.alignment: Qt.AlignHCenter
                Layout.margins: 2
                orientation: Qt.Vertical

                onMoved: changeZValue(value.toFixed(0));

                // Custom slider handle that displays the current value
                handle: Item {
                    x: parent.leftPadding + parent.availableWidth / 2 - headingHandleNub.width / 2
                    y: parent.topPadding + parent.visualPosition * (parent.availableHeight - headingHandleNub.height)

                    Rectangle {
                        id: headingHandleNub
                        color: headingHandleRect.color
                        radius: width * 0.5
                        width: 20
                        height: width
                    }
                    Rectangle {
                        id: headingHandleRect
                        height: childrenRect.height
                        width: childrenRect.width
                        radius: 3
                        x: headingHandleNub.x - width
                        y: headingHandleNub.y - height / 2 + headingHandleNub.height / 2
                        color: zValueSlider.background.children[0].color

                        Text {
                            id: headingValue
                            font.pixelSize: 14
                            padding: 3
                            horizontalAlignment: Qt.AlignHCenter
                            verticalAlignment: Qt.AlignVCenter
                            text: (zValueSlider.value).toFixed(0)
                            color: "white"
                        }
                    }
                }
            }
        }
    }
    // create a point with a z value of 70
    Point {
        id: sceneRelatedPoint
        x: -4.4610562
        y: 48.3902727
        z: 70
        spatialReference: SpatialReference { wkid: 4326 }
    }
    // create a point with a z value of 70
    Point {
        id: surfaceRelatedPoint
        x: -4.4609257
        y: 48.3903965
        z: 70
        spatialReference: SpatialReference { wkid: 4326 }
    }

    function changeZValue(zValue) {
        sceneView.graphicsOverlays.forEach( function(overlay) {
            overlay.graphics.forEach( function(graphic) {
                // create new graphic with the same existing information but a new Z-value
                const graphicPoint = ArcGISRuntimeEnvironment.createObject("Point", {
                                                                               x:graphic.geometry.x,
                                                                               y:graphic.geometry.y,
                                                                               z:zValue,
                                                                               spatialReference: graphic.geometry.spatialReference
                                                                           });
                graphic.geometry = graphicPoint;
            });
        });
    }
}

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