Create a feature collection layer to show a query result from a service feature table.
Use case
Consider a national wireless telecommunications company who wants to improve connectivity within areas of poor coverage. Their cell towers, cell tower radii and state boundaries data are held within service feature tables, which can be queried for states that don't meet a certain threshold of coverage. The query result can be used to create and display a single feature collection layer for analysis of areas requiring improved coverage.
How to use the sample
When launched, this sample displays a map with point features as a feature collection layer. Pan and zoom to explore the map.
How it works
- Perform a query using the
queryFeaturesAsync()method on aServiceFeatureTable. - Instantiate a
FeatureCollectionTablewith the result of the query. - Create a
FeatureCollectionand add the feature collection table to it. - Create a
FeatureCollectionLayerfrom the feature collection. - Add the feature collection layer to the map's
operationalLayerslist.
Relevant API
- FeatureCollection
- FeatureCollectionLayer
- FeatureCollectionTable
- FeatureLayer
- FeatureQueryResult
- FeatureTable
- QueryParameters
- ServiceFeatureTable
About the data
This application utilizes data from the wildfire feature service. It loads at full extent with features indicating wildfire response point features across the world.
Tags
layer, query, search, table
Sample Code
// [WriteFile Name=FeatureCollectionLayerQuery, Category=Layers] // [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 // sample headers #include "FeatureCollectionLayerQuery.h" // ArcGIS Maps SDK headers #include "FeatureCollection.h" #include "FeatureCollectionLayer.h" #include "FeatureCollectionTable.h" #include "FeatureQueryResult.h" #include "LayerListModel.h" #include "Map.h" #include "MapQuickView.h" #include "MapTypes.h" #include "QueryParameters.h" #include "ServiceFeatureTable.h" // Qt headers #include <QFuture> #include <QString> #include <QUuid> using namespace Esri::ArcGISRuntime; FeatureCollectionLayerQuery::FeatureCollectionLayerQuery(QQuickItem* parent /* = nullptr */): QQuickItem(parent) { } void FeatureCollectionLayerQuery::init() { // Register the map view for QML qmlRegisterType<MapQuickView>("Esri.Samples", 1, 0, "MapView"); qmlRegisterType<FeatureCollectionLayerQuery>("Esri.Samples", 1, 0, "FeatureCollectionLayerQuerySample"); } bool FeatureCollectionLayerQuery::busy() const { return m_busy; } void FeatureCollectionLayerQuery::setBusy(bool val) { if (val == m_busy) return; m_busy = val; emit busyChanged(); } void FeatureCollectionLayerQuery::componentComplete() { QQuickItem::componentComplete(); // find QML MapView component m_mapView = findChild<MapQuickView*>("mapView"); // Create a map using the oceans basemap m_map = new Map(BasemapStyle::ArcGISOceans, this); // Set map to map view m_mapView->setMap(m_map); //initialize service feature table to be queried m_featureTable = new ServiceFeatureTable(QUrl(QStringLiteral("https://sampleserver6.arcgisonline.com/arcgis/rest/services/Wildfire/FeatureServer/0")), this); //create query parameters QueryParameters queryParams; // 1=1 will give all the features from the table queryParams.setWhereClause("1=1"); m_featureTable->queryFeaturesAsync(queryParams).then(this, [this](FeatureQueryResult* featureQueryResult) { setBusy(false); if (!featureQueryResult) return; //create a feature collection table fromt the query results FeatureCollectionTable* featureCollectionTable = new FeatureCollectionTable(featureQueryResult, this); //create a feature collection from the above feature collection table FeatureCollection* featureCollection = new FeatureCollection(QList<FeatureCollectionTable*> {featureCollectionTable}, this); //create a feature collection layer FeatureCollectionLayer* featureCollectionLayer = new FeatureCollectionLayer(featureCollection, this); //add the layer to the operational layers array m_map->operationalLayers()->append(featureCollectionLayer); }); setBusy(true); }