Feature layer (dictionary renderer)

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Convert features into graphics to show them with mil2525d symbols.

screenshot

Use case

A dictionary renderer uses a style file along with a rule engine to display advanced symbology. This is useful for displaying features using precise military symbology.

How to use the sample

Pan and zoom around the map. Observe the displayed military symbology on the map.

How it works

  1. Create a Geodatabase using Geodatabase(geodatabasePath).
  2. Load the geodatabase asynchronously using Geodatabase::load().
  3. Instantiate a DictionarySymbolStyle using DictionarySymbolStyle::createFromFile(stylePath).
  4. Wait for geodatabase to completely load by connecting to Geodatabase::loadStatusChanged signal.
  5. Cycle through each GeodatabaseFeatureTable from the geodatabase using Geodatabase::geodatabaseFeatureTables().
  6. Create a FeatureLayer from each table within the geodatabase using FeatureLayer(GeodatabaseFeatureTable).
  7. Load the feature layer asynchronously with FeatureLayer::load().
  8. Wait for each layer to load using FeatureLayer::loadStatusChanged.
  9. After the last layer has loaded, then create a new Envelope from a union of the extents of all layers.
    • Set the envelope to be the Viewpoint of the map view using MapView::setViewpoint(Envelope).
  10. Add the feature layer to map using Map::operationalLayers()::append(FeatureLayer).
  11. Create DictionaryRenderer(DictionarySymbolStyle) and attach to the feature layer using FeatureLayer::setRenderer(DictionaryRenderer).

Relevant API

  • DictionaryRenderer
  • DictionarySymbolStyle

Offline Data

Read more about how to set up the sample's offline data here.

Link Local Location
Mil2525d Stylx File <userhome>/ArcGIS/Runtime/Data/styles/arcade_style/mil2525d.stylx
Military Overlay geodatabase <userhome>/ArcGIS/Runtime/Data/geodatabase/militaryoverlay.geodatabase

Tags

military, symbol

Sample Code

FeatureLayerDictionaryRenderer.cppFeatureLayerDictionaryRenderer.cppFeatureLayerDictionaryRenderer.hFeatureLayerDictionaryRenderer.qml
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// [WriteFile Name=FeatureLayerDictionaryRenderer, Category=Features]
// [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 "FeatureLayerDictionaryRenderer.h"

#include "DictionaryRenderer.h"
#include "FeatureLayer.h"
#include "Geodatabase.h"
#include "GeodatabaseFeatureTable.h"
#include "GeometryEngine.h"
#include "Map.h"
#include "MapQuickView.h"
#include "DictionarySymbolStyle.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

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

FeatureLayerDictionaryRenderer::~FeatureLayerDictionaryRenderer() = default;

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

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

  m_mapView = findChild<MapQuickView*>("mapView");
  // Create a map using the topo basemap
  Map* map = new Map(BasemapStyle::ArcGISTopographic, this);
  // set map on the map view
  m_mapView->setMap(map);

  m_geodatabase = new Geodatabase(m_dataPath + "/geodatabase/militaryoverlay.geodatabase", this);

  connect(m_geodatabase, &Geodatabase::loadStatusChanged, this, [this](LoadStatus gdbLoadStatus)
  {
    if (gdbLoadStatus == LoadStatus::Loaded)
    {
      /**
             * If the field names in your data don't match the contents of DictionarySymbolStyle::symbologyFieldNames(),
             * you must add key-value pairs to a QMap<QString, QString> and include this QMap when calling the
             * DictionaryRenderer constructor. The keys and values are like this:
             *
             *   "dictionaryFieldName1": "myFieldName1"
             *   "dictionaryFieldName2": "myFieldName2"
             *
             * The same principle applies to DictionarySymbolStyle::textFieldNames() for text attributes that appear
             * as part of military symbols.
             *
             * The following commented-out code demonstrates one way to do it, in a scenario where the dictionary
             * expects the field name "identity" but the database table contains the field "affiliation" instead,
             * and where the dictionary expects the field name "uniquedesignation" but the database table contains
             * the field "uniqueId" instead.
             */
      //            QMap<QString, QString> symbologyFieldOverrides;
      //            QMap<QString, QString> textFieldOverrides;
      //            symbologyFieldOverrides["identity"] = "affiliation";
      //            textFieldOverrides["uniquedesignation"] = "uniqueId";

      //! [Create Dictionary Symbol Style Cpp]
      const QString specType = QStringLiteral("mil2525d");
      const QString stylePath = m_dataPath + "/styles/arcade_style/mil2525d.stylx";
      DictionarySymbolStyle* dictionarySymbolStyle = DictionarySymbolStyle::createFromFile(stylePath, this);
      //! [Create Dictionary Symbol Style Cpp]

      Q_UNUSED(specType)

      const auto tables = m_geodatabase->geodatabaseFeatureTables();
      for (GeodatabaseFeatureTable* table : tables)
      {
        //! [Apply Dictionary Renderer Feature Layer Cpp]
        // Create a layer and set the feature table
        FeatureLayer* layer = new FeatureLayer(table, this);

        // Create a dictionary renderer and apply to the layer
        DictionaryRenderer* renderer = new DictionaryRenderer(dictionarySymbolStyle, this);
        layer->setRenderer(renderer);
        //! [Apply Dictionary Renderer Feature Layer Cpp]

        // Check to see if all layers have loaded
        connect(layer, &FeatureLayer::loadStatusChanged, this, [this](LoadStatus layerLoadStatus)
        {
          if (layerLoadStatus == LoadStatus::Loaded)
          {
            m_loadedLayerCount++;

            if (m_loadedLayerCount == m_geodatabase->geodatabaseFeatureTables().length())
            {
              /**
                             * If we get here, all the layers loaded. Union the extents and set
                             * the viewpoint.
                             */
              LayerListModel* layers = m_mapView->map()->operationalLayers();
              if (layers->size() > 0)
              {
                Envelope bbox = layers->at(0)->fullExtent();
                for (int j = 1; j < layers->size(); j++)
                {
                  bbox = GeometryEngine::unionOf(bbox, layers->at(j)->fullExtent());
                }
                m_mapView->setViewpointGeometry(bbox, 100);
              }

              emit allLayersLoaded();
            }
          }
        }, Qt::DirectConnection);

        /**
                 * Add the layer to the map. Inserting at index 0 puts the layer below previously added
                 * layers.
                 */
        m_mapView->map()->operationalLayers()->insert(0, layer);
      }
    }
  });
  m_geodatabase->load();
}

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