Graphics overlay (dictionary renderer)

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This sample demonstrates applying a dictionary renderer to graphics, in order to display military symbology without the need for a feature table.

screenshot

Use case

Use a dictionary renderer on a graphics overlay to display more transient data, such as military messages coming through a local tactical network.

How to use the sample

Pan and zoom to explore military symbols on the map.

How it works

  1. Create a new DictionarySymbolStyle(dictionaryPath).
  2. Create a new DictionaryRenderer(symbolDictionary).
  3. Create a new GraphicsOverlay
  4. Set the dictionary renderer to the graphics overlay.
  5. Parse through the XML and create a Graphic for each element:

i. Use the _wkid key to get the geometry's spatial reference. ii. Use the _control_points key to get the geometry's shape. iii. Create a geometry using the spatial reference and shape from above. iv. Create a Graphic for each attribute, utilizing its defined geometry. v. Add the graphic to the graphics overlay.

Relevant API

  • DictionaryRenderer
  • DictionarySymbolStyle
  • GraphicsOverlay

Offline data

To set up the sample's offline data, see the Use offline data in the samples section of the Qt Samples repository overview.

Link Local Location
Mil2525d Stylx File <userhome>/ArcGIS/Runtime/Data/styles/arcade_style/mil2525d.stylx
MIL-STD-2525D XML Message File <userhome>/ArcGIS/Runtime/Data/xml/arcade_style/Mil2525DMessages.xml

About the data

The sample opens to a view of the county Wiltshire, United Kingdom. It displays military symbols illustrating a simulated combat situation in the area.

Tags

defense, military, situational awareness, tactical, visualization

Sample Code

GODictionaryRenderer.cppGODictionaryRenderer.cppGODictionaryRenderer.hGODictionaryRenderer.qml
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// [WriteFile Name=GODictionaryRenderer, Category=DisplayInformation]
// [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 "GODictionaryRenderer.h"

#include "DictionaryRenderer.h"
#include "GraphicListModel.h"
#include "Map.h"
#include "MapQuickView.h"
#include "PolygonBuilder.h"
#include "MultipointBuilder.h"
#include "DictionarySymbolStyle.h"
#include "DictionarySymbolStyleConfiguration.h"

#include <QDir>
#include <QtCore/qglobal.h>

#ifdef Q_OS_IOS
#include <QStandardPaths>
#endif // Q_OS_IOS

using namespace Esri::ArcGISRuntime;

// helper method to get cross platform data path
namespace
{
QString defaultDataPath()
{
  QString dataPath;

#ifdef Q_OS_ANDROID
  dataPath = "/sdcard";
#elif defined Q_OS_IOS
  dataPath = QStandardPaths::writableLocation(QStandardPaths::DocumentsLocation);
#else
  dataPath = QDir::homePath();
#endif

  return dataPath;
}
} // namespace

const QString GODictionaryRenderer::FIELD_CONTROL_POINTS = QStringLiteral("_control_points");
const QString GODictionaryRenderer::FIELD_WKID = QStringLiteral("_wkid");

GODictionaryRenderer::GODictionaryRenderer(QQuickItem* parent) :
  QQuickItem(parent),
  m_dataPath(defaultDataPath() + "/ArcGIS/Runtime/Data")
{
}

GODictionaryRenderer::~GODictionaryRenderer() = default;

void GODictionaryRenderer::init()
{
  qmlRegisterType<MapQuickView>("Esri.Samples", 1, 0, "MapView");
  qmlRegisterType<GODictionaryRenderer>("Esri.Samples", 1, 0, "GODictionaryRendererSample");
}

bool GODictionaryRenderer::graphicsLoaded() const
{
  return m_graphicsLoaded;
}

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

  //! [Apply Dictionary Renderer Graphics Overlay Cpp]
  // Create graphics overlay
  m_graphicsOverlay = new GraphicsOverlay(this);

  // Create dictionary renderer and apply to the graphics overlay
  const QString specType = QStringLiteral("mil2525d");
  const QString styleLocation = m_dataPath + "/styles/arcade_style/mil2525d.stylx";
  DictionarySymbolStyle* dictionarySymbolStyle = DictionarySymbolStyle::createFromFile(styleLocation, this);

  // The style will be loaded automatically
  connect(dictionarySymbolStyle, &DictionarySymbolStyle::loadStatusChanged, this, [dictionarySymbolStyle]
  {
    if (dictionarySymbolStyle->loadStatus() == LoadStatus::Loaded)
    {
      const QList<DictionarySymbolStyleConfiguration*> dictionarySymbolStyleConfigurations = dictionarySymbolStyle->configurations();
      for (DictionarySymbolStyleConfiguration* dictionarySymbolStyleConfiguration : dictionarySymbolStyleConfigurations)
      {
        if (dictionarySymbolStyleConfiguration->name() == "model")
        {
          dictionarySymbolStyleConfiguration->setValue("ORDERED ANCHOR POINTS");
        }
      }
    }
  });

  //! [Apply Dictionary Renderer Graphics Overlay Cpp]
  Q_UNUSED(specType)

  DictionaryRenderer* renderer = new DictionaryRenderer(dictionarySymbolStyle, this);
  m_graphicsOverlay->setRenderer(renderer);
  // Create a map and give it to the MapView
  m_mapView = findChild<MapQuickView*>("mapView");
  m_map = new Map(BasemapStyle::ArcGISTopographic, this);

  parseXmlFile();

  m_mapView->graphicsOverlays()->append(m_graphicsOverlay);

  // The GraphicsOverlay will not have a valid extent until it is part of
  // a MapQuickView with a valid spatial referenence
  connect(m_mapView, &MapQuickView::spatialReferenceChanged, this, [this]()
  {
    zoomToGraphics();
  });

  m_mapView->setMap(m_map);
}

void GODictionaryRenderer::parseXmlFile()
{
  bool readingMessage = false;
  QVariantMap elementValues;
  QString currentElementName;

  QFile xmlFile(m_dataPath + "/xml/arcade_style/Mil2525DMessages.xml");

  // Open the file for reading
  if (xmlFile.isOpen())
  {
    xmlFile.reset();
  }
  else
  {
    xmlFile.open(QIODevice::ReadOnly | QIODevice::Text);
  }
  m_xmlParser.setDevice(&xmlFile);

  // Traverse the XML in a loop
  while (!m_xmlParser.atEnd())
  {
    m_xmlParser.readNext();

    // Is this the start or end of a message element?
    if (m_xmlParser.name() == "message")
    {
      if (!readingMessage)
      {
        // This is the start of a message element.
        elementValues.clear();
      }
      else
      {
        // This is the end of a message element. Here we have a complete message that defines
        // a military feature to display on the map. Create a graphic from its attributes.
        createGraphic(elementValues);
      }
      // Either we just started reading a message, or we just finished reading a message.
      readingMessage = !readingMessage;
    }
    // Are we already inside a message element?
    else if (readingMessage)
    {
      // Is this the start of an element inside a message?
      if (m_xmlParser.isStartElement())
      {
        // Remember which element we're reading
        currentElementName = m_xmlParser.name().toString();
      }
      // Is this text?
      else if (m_xmlParser.isCharacters())
      {
        // Is this text inside an element?
        if (!currentElementName.isEmpty())
        {
          // Get the text and store it as the current element's value
          QStringRef trimmedText = m_xmlParser.text().trimmed();
          if (!trimmedText.isEmpty())
          {
            elementValues[currentElementName] = trimmedText.toString();
          }
        }
      }
    }
  }

  emit graphicsLoadedChanged();
}

void GODictionaryRenderer::createGraphic(QVariantMap rawAttributes)
{
  // If _wkid was absent, use WGS 1984 (4326) by default.
  const int wkid = rawAttributes.count(FIELD_WKID) > 0 ? rawAttributes[FIELD_WKID].toInt() : 4326;
  const SpatialReference sr(wkid);
  const QStringList pointStrings = rawAttributes[FIELD_CONTROL_POINTS].toString().split(";");

  Geometry geom;
  if (pointStrings.length() == 1)
  {
    // It's a point
    const QStringList coords = pointStrings[0].split(",");
    geom = Point(coords[0].toDouble(), coords[1].toDouble(), sr);
  }
  else {
    // It's a multipoint
    MultipointBuilder* builder = new MultipointBuilder(sr, this);
    PointCollection* collection = new PointCollection(sr, this);
    for (const QString& pointString : pointStrings)
    {
      const QStringList coords = pointString.split(",");
      if (coords.length() >= 2)
        collection->addPoint(coords[0].toDouble(), coords[1].toDouble());
    }
    builder->setPoints(collection);
    geom = builder->toGeometry();
  }

  if (!geom.isEmpty())
  {
    // Get rid of _control_points and _wkid. They are not needed in the graphic's
    // attributes.
    rawAttributes.remove(FIELD_CONTROL_POINTS);
    rawAttributes.remove(FIELD_WKID);

    Graphic* graphic = new Graphic(geom, rawAttributes, this);
    m_graphicsOverlay->graphics()->append(graphic);
  }
}

void GODictionaryRenderer::zoomToGraphics()
{
  if (m_graphicsOverlay)
    m_mapView->setViewpointGeometry(m_graphicsOverlay->extent(), 20);
}

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