Display a WFS layer

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Sample viewer app

Display a layer from a WFS service, requesting only features for the current extent.

screenshot

Use case

WFS is an open standard with functionality similar to ArcGIS feature services. Runtime support for WFS allows you to interoperate with open systems, which are often used in inter-agency efforts, like those for disaster relief.

How to use the sample

Pan and zoom to see features within the current map extent.

How it works

  1. Create a WfsFeatureTable with a URL and table name.
  2. Create a FeatureLayer from the feature table and add it to the map.
  3. Listen for the MapView.navigatingChanged signal to detect when the user has stopped navigating the map.
  4. When the user is finished navigating, use populateFromService to load the table with data for the current visible extent.

Relevant API

  • FeatureLayer
  • WfsFeatureTable
  • WfsFeatureTable.populateFromService

About the data

This service shows building footprints for downtown Seattle. For additional information, see the underlying service on ArcGIS Online.

Tags

browse, catalog, feature, interaction cache, layers, OGC, service, web, WFS

Sample Code

DisplayWfsLayer.qml
                                                                                                   
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// [WriteFile Name=DisplayWfsLayer, 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]

import QtQuick 2.6
import Esri.ArcGISRuntime 100.12

Rectangle {
    id: rootRectangle
    clip: true
    width: 800
    height: 600

    MapView {
        id: mapView
        anchors.fill: parent

        Map {
            Basemap {
                initStyle: Enums.BasemapStyleArcGISTopographic
            }

            FeatureLayer {
                // Create WFS Feature Table from Get Capabilities URL and table name
                WfsFeatureTable {
                    id: wfsFeatureTable
                    url: "https://dservices2.arcgis.com/ZQgQTuoyBrtmoGdP/arcgis/services/Seattle_Downtown_Features/WFSServer?service=wfs&request=getcapabilities"
                    tableName: "Seattle_Downtown_Features:Buildings"

                    // Set feature request mode to manual - only manual is supported at v100.5.
                    // In this mode, you must manually populate the table - panning and zooming
                    // won't request features automatically.
                    featureRequestMode: Enums.FeatureRequestModeManualCache

                    // Once the table is loaded, request to populate the cache
                    onLoadStatusChanged: {
                        if (loadStatus !== Enums.LoadStatusLoaded)
                            return;

                        populateWfsFeatureTable();
                    }
                }

                // Assign a renderer to the layer
                SimpleRenderer {
                    SimpleLineSymbol {
                        color: "red"
                        width: 3
                        style: Enums.SimpleLineSymbolStyleSolid
                    }
                }
            }

            // Set initial viewpoint on the map
            ViewpointExtent {
                Envelope {
                    id: initialExtent
                    xMin: -122.341581
                    yMin: 47.613758
                    xMax: -122.332662
                    yMax: 47.617207
                    spatialReference: SpatialReference { wkid: 4326 }
                }
            }
        }

        // Populate with more features once done navigating to new extent
        onNavigatingChanged: {
            if (navigating) {
                return;
            }

            populateWfsFeatureTable();
        }
    }

    function populateWfsFeatureTable() {
        // Create query parameters
        const params = ArcGISRuntimeEnvironment.createObject("QueryParameters", {
                                                                 geometry: mapView.visibleArea.extent,
                                                                 spatialRelationship: Enums.SpatialRelationshipIntersects
                                                             });

        // Populate features based on query
        wfsFeatureTable.populateFromService(params, false, ["*"]);
    }
}

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