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Load a WFS feature table using an XML query.
Use case
QueryParameters
objects can't represent all possible queries that can be made against a WFS feature service. For example, query parameters don't support wildcard searches. You can provide queries as raw XML strings, allowing you to access query functionality not available with QueryParameters
.
How to use the sample
Run the sample and view the data loaded from the the WFS feature table.
How it works
Create a WfsFeatureTable
and a FeatureLayer
to visualize the table.
Set the feature request mode to ManualCache
.
Call populateFromService
to populate the table with only those features returned by the XML query.
Relevant API
FeatureLayer
WfsFeatureTable
WfsFeatureTable::axisOrder
WfsFeatureTable::populateFromService
About the data
This service shows trees in downtown Seattle and the surrounding area. An XML-encoded GetFeature
request is used to limit results to only trees of the genus Tilia .
For additional information, see the underlying service on ArcGIS Online .
feature, OGC, query, service, web, WFS, XML
Sample CodeLoadWfsXmlQuery.cpp LoadWfsXmlQuery.cpp LoadWfsXmlQuery.h LoadWfsXmlQuery.qml
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// [WriteFile Name=LoadWfsXmlQuery, Category=Layers]
// [Legal]
// Copyright 2019 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 "LoadWfsXmlQuery.h"
# include "Map.h"
# include "MapQuickView.h"
# include "FeatureLayer.h"
# include "WfsFeatureTable.h"
# include "Error.h"
# include "MapTypes.h"
# include "TaskWatcher.h"
# include "LayerListModel.h"
# include "GeodatabaseTypes.h"
# include "Envelope.h"
using namespace Esri::ArcGISRuntime;
namespace
{
const QString xmlQueryString = R"(
<wfs:GetFeature service="WFS" version="2.0.0"
xmlns:Seattle_Downtown_Features="https://dservices2.arcgis.com/ZQgQTuoyBrtmoGdP/arcgis/services/Seattle_Downtown_Features/WFSServer"
xmlns:wfs="http://www.opengis.net/wfs/2.0"
xmlns:fes="http://www.opengis.net/fes/2.0"
xmlns:gml="http://www.opengis.net/gml/3.2">
<wfs:Query typeNames="Seattle_Downtown_Features:Trees">
<fes:Filter>
<fes:PropertyIsLike wildCard="*" escapeChar="\">
<fes:ValueReference>Trees:SCIENTIFIC</fes:ValueReference>
<fes:Literal>Tilia *</fes:Literal>
</fes:PropertyIsLike>
</fes:Filter>
</wfs:Query>
</wfs:GetFeature>)" ;
}
LoadWfsXmlQuery:: LoadWfsXmlQuery (QObject* parent /* = nullptr */ ):
QObject (parent),
m_map ( new Map (BasemapStyle::ArcGISNavigation, this ))
{
// create WFS Feature Table
const QUrl featureTableUrl ( "https://dservices2.arcgis.com/ZQgQTuoyBrtmoGdP/arcgis/services/Seattle_Downtown_Features/WFSServer?service=wfs&request=getcapabilities" ) ;
WfsFeatureTable* wfsFeatureTable = new WfsFeatureTable (featureTableUrl,
"Seattle_Downtown_Features:Trees" ,
this );
wfsFeatureTable-> setFeatureRequestMode (FeatureRequestMode::ManualCache);
// connect to feature table doneLoading signal
connect (wfsFeatureTable, &WfsFeatureTable::doneLoading, this , [wfsFeatureTable, this ]( const Error& e)
{
if (!e. isEmpty ())
return ;
// populate the table with XML Query
wfsFeatureTable-> populateFromService (xmlQueryString, true );
// set the viewpoint to the center of the extent
m_mapView-> setViewpointGeometry (wfsFeatureTable-> extent (), 50 );
});
// create Feature Layer
FeatureLayer* featureLayer = new FeatureLayer (wfsFeatureTable, this );
// add layer to the map
m_map-> operationalLayers ()-> append (featureLayer);
}
LoadWfsXmlQuery::~ LoadWfsXmlQuery () = default ;
void LoadWfsXmlQuery::init ()
{
// Register the map view for QML
qmlRegisterType<MapQuickView>( "Esri.Samples" , 1 , 0 , "MapView" );
qmlRegisterType<LoadWfsXmlQuery>( "Esri.Samples" , 1 , 0 , "LoadWfsXmlQuerySample" );
}
MapQuickView* LoadWfsXmlQuery::mapView () const
{
return m_mapView;
}
// Set the view (created in QML)
void LoadWfsXmlQuery::setMapView (MapQuickView* mapView)
{
if (!mapView || mapView == m_mapView)
return ;
m_mapView = mapView;
m_mapView-> setMap (m_map);
emit mapViewChanged () ;
}