Feature layer (GeoPackage)

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Sample viewer app

Display features from a local GeoPackage.

screenshot

Use case

A GeoPackage is an OGC standard, making it useful when your project requires an open source data format or when other, non-ArcGIS systems may be creating the data. Accessing data from a local GeoPackage is useful when working in an environment that has an inconsistent internet connection or that does not have an internet connection at all. For example, a department of transportation field worker might source map data from a GeoPackage when conducting signage inspections in rural areas with poor network coverage.

How to use the sample

Pan and zoom around the map. View the data loaded from the geopackage.

How it works

  1. Create a GeoPackage passing the URL string into the constructor.
  2. Load the GeoPackage with GeoPackage::load
  3. When it's done loading, get the GeoPackageFeatureTable objects from the geopackage with geoPackage::geoPackageFeatureTables()
  4. Create a FeatureLayer(featureTable) for the first feature table and add it to the map as an operational layer using, map::operationalLayers()::append(featureLayer)

Relevant API

  • FeatureLayer
  • GeoPackage
  • GeoPackageFeatureTable
  • Map

Offline data

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

Link Local Location
Aurora, Colorado GeoPackage <userhome>/ArcGIS/Runtime/Data/gpkg/AuroraCO.gpkg

About the data

The map shows point locations of public art installations in Aurora, Colorado.

Tags

feature table, geopackage, gpkg, OGC, package, standards

Sample Code

FeatureLayer_GeoPackage.cppFeatureLayer_GeoPackage.cppFeatureLayer_GeoPackage.hFeatureLayer_GeoPackage.qml
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// [WriteFile Name=FeatureLayer_GeoPackage, Category=Features]
// [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]

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

#include "FeatureLayer_GeoPackage.h"

#include "Map.h"
#include "MapQuickView.h"
#include "GeoPackage.h"
#include "GeoPackageFeatureTable.h"
#include "FeatureLayer.h"
#include "Point.h"
#include "Viewpoint.h"

#include <QUrl>
#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

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

void FeatureLayer_GeoPackage::init()
{
  // Register the map view for QML
  qmlRegisterType<MapQuickView>("Esri.Samples", 1, 0, "MapView");
  qmlRegisterType<FeatureLayer_GeoPackage>("Esri.Samples", 1, 0, "FeatureLayer_GeoPackageSample");
}

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

  // find QML MapView component
  m_mapView = findChild<MapQuickView*>("mapView");

  // Create a map using the light gray basemap
  m_map = new Map(BasemapStyle::ArcGISLightGray, this);

  // Set an initial viewpoint
  const Point pt(-104.8319, 39.7294, SpatialReference(4326));
  const Viewpoint vp(pt, 200000);
  m_map->setInitialViewpoint(vp);

  // Create the GeoPackage
  const QString dataPath = defaultDataPath() + "/ArcGIS/Runtime/Data/gpkg/";
  GeoPackage* gpkg = new GeoPackage(dataPath + "AuroraCO.gpkg", this);

  // Connect to GeoPackage::doneLoading
  connect(gpkg, &GeoPackage::doneLoading, this, [this, gpkg](Error e)
  {
    if (!e.isEmpty())
      return;

    if (!(gpkg->geoPackageFeatureTables().size() > 0))
      return;

    GeoPackageFeatureTable* gpkgFeatureTable = gpkg->geoPackageFeatureTables().at(0);
    FeatureLayer* featureLayer = new FeatureLayer(gpkgFeatureTable, this);
    m_map->operationalLayers()->append(featureLayer);
  });

  // Connect to Map::doneLoading
  connect(m_map, &Map::doneLoading, this, [gpkg](Error e)
  {
    if (!e.isEmpty())
      return;

    // load the GeoPackage
    gpkg->load();
  });

  // Set map to map view
  m_mapView->setMap(m_map);
}

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