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Browse an OGC API feature service for layers and add them to the map.
Use case
OGC API standards are used for sharing geospatial data on the web. As an open standard, the OGC API aims to improve access to geospatial or location information and could be a good choice for sharing data internationally or between organizations. That data could be of any type, including, for example, transportation layers shared between government organizations and private businesses.
How to use the sample
Select a layer to display from the drop-down list of layers available from the OGC API service. The Daraa data is used as the default feature service, however, alternative feature services can be used.
How it works
Create an OgcFeatureService
object with a URL to an OGC API feature service.
Obtain the OgcFeatureServiceInfo
from OgcFeatureService.ServiceInfo
.
Create a list of feature collections from the OgcFeatureServiceInfo.FeatureCollectionInfos
.
When a feature collection is selected, create an OgcFeatureCollectionTable
from the OgcFeatureCollectionInfo
.
Populate the OgcFeatureCollectionTable
using PopulateFromService
with QueryParameters
that contain a MaxFeatures
property.
Create a feature layer from the feature table.
Add the feature layer to the map.
Relevant API
OgcFeatureCollectionInfo
OgcFeatureCollectionTable
OgcFeatureService
OgcFeatureServiceInfo
About the data
The Daraa, Syria test data is OpenStreetMap data converted to the Topographic Data Store schema of NGA.
See the OGC API website for more information on the OGC API family of standards.
browse, catalog, feature, layers, OGC, OGC API, service, web
Sample CodeBrowseOGCAPIFeatureService.cpp BrowseOGCAPIFeatureService.cpp BrowseOGCAPIFeatureService.h BrowseOGCAPIFeatureService.qml
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// [WriteFile Name=BrowseOGCAPIFeatureService, Category=Layers]
// [Legal]
// Copyright 2021 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 "BrowseOGCAPIFeatureService.h"
# include "FeatureLayer.h"
# include "Map.h"
# include "MapQuickView.h"
# include "OgcFeatureCollectionInfo.h"
# include "OgcFeatureCollectionTable.h"
# include "OgcFeatureService.h"
# include "OgcFeatureServiceInfo.h"
# include "Error.h"
# include "MapTypes.h"
# include "TaskWatcher.h"
# include "LayerListModel.h"
# include "QueryParameters.h"
# include "GeodatabaseTypes.h"
# include "Envelope.h"
# include <QQmlEngine>
using namespace Esri::ArcGISRuntime;
BrowseOGCAPIFeatureService:: BrowseOGCAPIFeatureService (QObject* parent /* = nullptr */ ):
QObject (parent),
m_map ( new Map (BasemapStyle::ArcGISTopographic, this ))
{
// Initialise OGC feature service
m_featureServiceUrl = "https://demo.ldproxy.net/daraa" ;
loadFeatureService (m_featureServiceUrl);
}
BrowseOGCAPIFeatureService::~ BrowseOGCAPIFeatureService () = default ;
void BrowseOGCAPIFeatureService::init ()
{
// Register the map view for QML
qmlRegisterType<MapQuickView>( "Esri.Samples" , 1 , 0 , "MapView" );
qmlRegisterType<BrowseOGCAPIFeatureService>( "Esri.Samples" , 1 , 0 , "BrowseOGCAPIFeatureServiceSample" );
}
MapQuickView* BrowseOGCAPIFeatureService::mapView () const
{
return m_mapView;
}
// Set the view (created in QML)
void BrowseOGCAPIFeatureService::setMapView (MapQuickView* mapView)
{
if (!mapView || mapView == m_mapView)
return ;
m_mapView = mapView;
m_mapView-> setMap (m_map);
emit mapViewChanged () ;
}
QUrl BrowseOGCAPIFeatureService::featureServiceUrl () const
{
return m_featureServiceUrl;
}
QStringList BrowseOGCAPIFeatureService::featureCollectionList () const
{
return m_featureCollectionList;
}
QString BrowseOGCAPIFeatureService::errorMessage () const
{
return m_errorMessage;
}
void BrowseOGCAPIFeatureService::setErrorMessage ( const QString& message)
{
m_errorMessage = message;
emit errorMessageChanged () ;
}
void BrowseOGCAPIFeatureService::handleError ( const Esri::ArcGISRuntime::Error& error)
{
if (error. additionalMessage (). isEmpty ())
setErrorMessage (error. message ());
else
setErrorMessage (error. message () + "\n" + error. additionalMessage ());
}
void BrowseOGCAPIFeatureService::loadFeatureService ( const QUrl& url)
{
if (m_featureService && m_featureService-> loadStatus () == LoadStatus::Loading)
return ;
clearExistingFeatureService ();
// Instantiate new OGCFeatureService object using url
m_featureService = new OgcFeatureService (url, this );
// Retrieve collection info when feature service has loaded
connect (m_featureService, &OgcFeatureService::doneLoading, this , &BrowseOGCAPIFeatureService::retrieveCollectionInfos);
// Connect errorOccurred to handleError()
connect (m_featureService, &OgcFeatureService::errorOccurred, this , &BrowseOGCAPIFeatureService::handleError);
// Connect to loadingChanged() to enable and disable UI buttons
connect (m_featureService, &OgcFeatureService::loadStatusChanged, this , &BrowseOGCAPIFeatureService::serviceOrFeatureLoadingChanged);
m_featureService-> load ();
}
void BrowseOGCAPIFeatureService::clearExistingFeatureService ()
{
m_collectionInfo. clear ();
if (m_serviceInfo != nullptr )
{
delete m_serviceInfo;
m_serviceInfo = nullptr ;
}
if (m_featureService != nullptr )
{
delete m_featureService;
m_featureService = nullptr ;
}
m_featureCollectionList. clear ();
emit featureCollectionListChanged () ;
}
void BrowseOGCAPIFeatureService::retrieveCollectionInfos ()
{
// Assign OGC service metadata to m_serviceInfo property
m_serviceInfo = m_featureService-> serviceInfo ();
// Assign information from each feature collection to the m_collectionInfo property
m_collectionInfo = m_serviceInfo-> featureCollectionInfos ();
createFeatureCollectionList ();
}
void BrowseOGCAPIFeatureService::createFeatureCollectionList ()
{
m_featureCollectionList. clear ();
// Populate list with names of each feature collection
for (OgcFeatureCollectionInfo* info : qAsConst (m_collectionInfo))
{
m_featureCollectionList. push_back (info-> title ());
}
emit featureCollectionListChanged () ;
}
void BrowseOGCAPIFeatureService::loadService ( const QUrl& urlFromInterface)
{
m_featureServiceUrl = urlFromInterface;
emit urlChanged () ;
loadFeatureService (m_featureServiceUrl);
}
void BrowseOGCAPIFeatureService::loadFeatureCollection ( int selectedFeature)
{
clearExistingFeatureLayer ();
// Create a CollectionInfo object from the selected feature collection
OgcFeatureCollectionInfo* info = m_collectionInfo[selectedFeature];
// Assign the CollectedInfo to the m_featureCollectionTable property
m_featureCollectionTable = new OgcFeatureCollectionTable (info, this );
// Set the feature request mode to manual (only manual is currently supported)
// In this mode you must manually populate the table - panning and zooming won't request features automatically
m_featureCollectionTable-> setFeatureRequestMode (FeatureRequestMode::ManualCache);
// Populate the OGC feature collection table
QueryParameters queryParameters;
queryParameters. setMaxFeatures ( 1000 );
m_featureCollectionTable-> populateFromService (queryParameters, false , QStringList{ /* empty */ });
// Create new Feature Layer from selected collection
m_featureLayer = new FeatureLayer (m_featureCollectionTable, this );
// Add feature layer to operational layers when it has finished loading
connect (m_featureLayer, &FeatureLayer::doneLoading, this , &BrowseOGCAPIFeatureService::addFeatureLayerToMap);
// Connect errorOccurred to handleError()
connect (m_featureLayer, &FeatureLayer::errorOccurred, this , &BrowseOGCAPIFeatureService::handleError);
// Connect to loadingChanged() to enable and disable UI buttons
connect (m_featureLayer, &FeatureLayer::loadStatusChanged, this , &BrowseOGCAPIFeatureService::serviceOrFeatureLoadingChanged);
m_featureLayer-> load ();
}
void BrowseOGCAPIFeatureService::clearExistingFeatureLayer ()
{
if (m_featureCollectionTable != nullptr )
{
delete m_featureCollectionTable;
m_featureCollectionTable = nullptr ;
}
if (m_featureLayer != nullptr )
{
delete m_featureLayer;
m_featureLayer = nullptr ;
}
}
void BrowseOGCAPIFeatureService::addFeatureLayerToMap ()
{
// Adjust the viewpoint to match the extent of the layer
m_mapView-> setViewpointGeometry (m_featureLayer-> fullExtent ());
// Clear any existing layers and add current layer to map
m_map-> operationalLayers ()-> clear ();
m_map-> operationalLayers ()-> append (m_featureLayer);
}
bool BrowseOGCAPIFeatureService::serviceOrFeatureLoading () const
{
if (m_featureService && m_featureService-> loadStatus () == LoadStatus::Loading)
return true ;
else if (m_featureLayer && m_featureLayer-> loadStatus () == LoadStatus::Loading)
return true ;
return false ;
}