Surface placement

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Sample viewer app

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.cppSurface_Placement.cppSurface_Placement.hSurface_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]

#ifdef PCH_BUILD
#include "pch.hpp"
#endif // PCH_BUILD

#include "Surface_Placement.h"

#include "ArcGISSceneLayer.h"
#include "ArcGISTiledElevationSource.h"
#include "Camera.h"
#include "Graphic.h"
#include "GraphicsOverlay.h"
#include "Point.h"
#include "Scene.h"
#include "SceneQuickView.h"
#include "SimpleMarkerSymbol.h"
#include "SpatialReference.h"
#include "TextSymbol.h"
#include "Viewpoint.h"

using namespace Esri::ArcGISRuntime;

Surface_Placement::Surface_Placement(QQuickItem* parent /* = nullptr */):
  QQuickItem(parent)
{
}

Surface_Placement::~Surface_Placement() = default;

void Surface_Placement::init()
{
  qmlRegisterType<SceneQuickView>("Esri.Samples", 1, 0, "SceneView");
  qmlRegisterType<Surface_Placement>("Esri.Samples", 1, 0, "SurfacePlacementSample");
}

void Surface_Placement::componentComplete()
{
  QQuickItem::componentComplete();

  //! [Create Scene API snippet]
  // Create a scene with the imagery basemap and world elevation surface
  m_sceneView = findChild<SceneQuickView*>("sceneView");
  Scene* scene = new Scene(BasemapStyle::ArcGISImageryStandard, this);
  Surface* surface = new Surface(this);
  surface->elevationSources()->append(new ArcGISTiledElevationSource(QUrl("https://elevation3d.arcgis.com/arcgis/rest/services/WorldElevation3D/Terrain3D/ImageServer"), this));
  scene->setBaseSurface(surface);

  // Create scene layer from the Brest, France scene server.
  ArcGISSceneLayer* sceneLayer = new ArcGISSceneLayer(QUrl("https://tiles.arcgis.com/tiles/P3ePLMYs2RVChkJx/arcgis/rest/services/Buildings_Brest/SceneServer"), this);
  scene->operationalLayers()->append(sceneLayer);
  //! [Create Scene API snippet]

  // set an initial viewpoint
  const Point initialViewPoint(-4.45968, 48.3889, 37.9922);
  const Camera camera(initialViewPoint, 329.91, 96.6632, 0);
  const Viewpoint viewpoint(initialViewPoint, camera);
  scene->setInitialViewpoint(viewpoint);

  // set the scene to the scene view
  m_sceneView->setArcGISScene(scene);

  // add graphics overlays and set surface placement
  addGraphicsOverlays();

  // add graphics
  addGraphics();
}

void Surface_Placement::addGraphicsOverlays()
{
  // Graphics overlay with draped billboarded surface placement
  m_drapedBillboardedOverlay = new GraphicsOverlay(this);
  m_drapedBillboardedOverlay->setSceneProperties(LayerSceneProperties(SurfacePlacement::DrapedBillboarded));
  m_sceneView->graphicsOverlays()->append(m_drapedBillboardedOverlay);

  // Graphics overlay with draped flat surface placement
  m_drapedFlatOverlay = new GraphicsOverlay(this);
  m_drapedFlatOverlay->setSceneProperties(LayerSceneProperties(SurfacePlacement::DrapedFlat));
  m_drapedFlatOverlay->setVisible(false);
  m_sceneView->graphicsOverlays()->append(m_drapedFlatOverlay);

  // Graphics overlay with relative surface placement
  m_relativeOverlay = new GraphicsOverlay(this);
  m_relativeOverlay->setSceneProperties(LayerSceneProperties(SurfacePlacement::Relative));
  m_sceneView->graphicsOverlays()->append(m_relativeOverlay);

  // Graphics overlay with relative to scene surface placement
  m_relativeToSceneOverlay = new GraphicsOverlay(this);
  m_relativeToSceneOverlay->setSceneProperties(LayerSceneProperties(SurfacePlacement::RelativeToScene));
  m_sceneView->graphicsOverlays()->append(m_relativeToSceneOverlay);

  // Graphics overlay with absolute surface placement
  m_absoluteOverlay = new GraphicsOverlay(this);
  m_absoluteOverlay->setSceneProperties(LayerSceneProperties(SurfacePlacement::Absolute));
  m_sceneView->graphicsOverlays()->append(m_absoluteOverlay);
}

void Surface_Placement::addGraphics()
{
  // create point for the scene related graphic with a z value of 70
  const Point sceneRelatedPoint(-4.4610562, 48.3902727, 70, SpatialReference::wgs84());

  // create point for the surface related graphics with z value of 70
  const Point surfaceRelatedPoint(-4.4609257, 48.3903965 , 70, SpatialReference::wgs84());

  // create simple marker symbol
  SimpleMarkerSymbol* simpleMarkerSymbol = new SimpleMarkerSymbol(SimpleMarkerSymbolStyle::Triangle, QColor("red"), 20, this);

  // create text symbols
  TextSymbol* drapedBillboardedText = new TextSymbol("DRAPED BILLBOARDED", QColor("blue"), 20, HorizontalAlignment::Left, VerticalAlignment::Middle, this);
  drapedBillboardedText->setOffsetX(20);
  TextSymbol* drapedFlatText = new TextSymbol("DRAPED FLAT", QColor("blue"), 20, HorizontalAlignment::Left, VerticalAlignment::Middle, this);
  drapedFlatText->setOffsetX(20);
  TextSymbol* relativeText = new TextSymbol("RELATIVE", QColor("blue"), 20, HorizontalAlignment::Left, VerticalAlignment::Middle, this);
  relativeText->setOffsetX(20);
  TextSymbol* relativeToSceneText = new TextSymbol("RELATIVE TO SCENE", QColor("blue"), 20, HorizontalAlignment::Right, VerticalAlignment::Middle, this);
  relativeToSceneText->setOffsetX(-20);
  TextSymbol* absoluteText = new TextSymbol("ABSOLUTE", QColor("blue"), 20, HorizontalAlignment::Left, VerticalAlignment::Middle, this);
  absoluteText->setOffsetX(20);

  // add graphics to each overlay
  // Graphics will be draped on the surface of the scene and will always face the camera.
  m_drapedBillboardedOverlay->graphics()->append(new Graphic(surfaceRelatedPoint, simpleMarkerSymbol));
  m_drapedBillboardedOverlay->graphics()->append(new Graphic(surfaceRelatedPoint, drapedBillboardedText));

  // Graphics will be draped on the surface of the scene
  m_drapedFlatOverlay->graphics()->append(new Graphic(surfaceRelatedPoint, simpleMarkerSymbol));
  m_drapedFlatOverlay->graphics()->append(new Graphic(surfaceRelatedPoint, drapedFlatText));

  // Graphics will be placed at z value relative to the surface
  m_relativeOverlay->graphics()->append(new Graphic(surfaceRelatedPoint, simpleMarkerSymbol));
  m_relativeOverlay->graphics()->append(new Graphic(surfaceRelatedPoint, relativeText));

  // Graphics will be placed at z value relative to the scene
  m_relativeToSceneOverlay->graphics()->append(new Graphic(sceneRelatedPoint, simpleMarkerSymbol));
  m_relativeToSceneOverlay->graphics()->append(new Graphic(sceneRelatedPoint, relativeToSceneText));

  // Graphics will be placed at absolute z value
  m_absoluteOverlay->graphics()->append(new Graphic(surfaceRelatedPoint, simpleMarkerSymbol));
  m_absoluteOverlay->graphics()->append(new Graphic(surfaceRelatedPoint, absoluteText));
}

void Surface_Placement::changeDrapedVisibility()
{
  m_drapedFlatOverlay->setVisible(!m_drapedFlatOverlay->isVisible());
  m_drapedBillboardedOverlay->setVisible(!m_drapedBillboardedOverlay->isVisible());
}

void Surface_Placement::changeZValue(double zValue)
{
  for (GraphicsOverlay* overlay : *m_sceneView->graphicsOverlays())
  {
    for (Graphic* graphic : *overlay->graphics())
    {
      // create new graphic with the same existing information but a new Z-value
      const Point graphicPoint{graphic->geometry()};
      const Point point{graphicPoint.x(), graphicPoint.y(), zValue, graphicPoint.spatialReference()};
      graphic->setGeometry(point);
    }
  }
}

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