Feature collection layer

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Create a Feature Collection Layer from a Feature Collection Table, and add it to a map.

screenshot

Use case

A Feature Collection allows easily importing external data (such as CSV files), as well as creating custom schema for data that is in non-standardized format. This data can then be used to populate a Feature Collection Table, and displayed in a Feature Collection Layer using the attributes and geometries provided in the external data source. For example, an electricity supplier could use this functionality to visualize existing location data of coverage areas (polygons), power stations (points), transmission lines (polylines), and others.

How to use the sample

When launched, this sample displays a FeatureCollectionLayer with a Point, Polyline and Polygon geometry. Pan and zoom to explore the scene.

How it works

A FeatureCollectionLayer is created from a FeatureCollection and is added to the map's operational layers. Then, a point FeatureCollectionTable, a polyline FeatureCollectionTable, and a polygon FeatureCollectionTable are created, and their schemas and renderers are defined. Next, features are added to each table, and each table is added to the FeatureCollection. In this case, hardcoded features are added to the tables for display on the map. However, a common use case is to read a CSV or some other data source, and to popuplate the table with the attributes and geometry provided in the external data source.

  1. Create a FeatureCollectionLayer using a new feature collection,.
  2. Add the feature collection layer to the Map.
  3. Create a FeatureCollectionTable for the GeometryTypes Point, Polyline, and Polygon, FeatureCollectionTable(fields, geometryType, spatialRefernce)

    • Additionally, pass in a list of Field objects to represent the table's schema. In this case a field of type String named name is added.
  4. Assign a SimpleRenderer to each table to render any Features from that table using the Symbol that was set.
  5. Add the feature collection table to the feature collection, FeatureCollection.tables.addFeature(featureCollectionTable).
  6. Use the createFeature method to create a feature from the feature collection table, passing an attribute and geometry for that feature, FeatureCollectionTable.createFeature(attributes, geometry).
  7. Add new features to the table, FeatureCollectionTable.addFeature(feature).

Relevant API

  • Feature
  • FeatureCollection
  • FeatureCollectionLayer
  • FeatureCollectionTable
  • Field
  • SimpleRenderer

Tags

collection, feature, layers, table

Sample Code

Feature_Collection_Layer.qml
                                                                                                                                                                                  
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// [WriteFile Name=Feature_Collection_Layer, Category=Layers]
// [Legal]
// Copyright 2016 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.BasemapStyleArcGISOceans
            }

            // Declare a FeatureCollectionLayer
            FeatureCollectionLayer {

                // Create a FeatureCollection inside the
                FeatureCollection {

                    // Create a Point FeatureCollectionTable inside the FeatureCollection
                    FeatureCollectionTable {
                        id: pointsTable

                        // define the schema of the table
                        geometryType: Enums.GeometryTypePoint
                        spatialReference: SpatialReference { wkid: 4326 }
                        Field {
                            id: placeField
                            alias: "Place Name"
                            name: "Place"
                            length: 50
                            fieldType: Enums.FieldTypeText
                        }

                        // define the renderer
                        SimpleRenderer {
                            SimpleMarkerSymbol {
                                style: Enums.SimpleMarkerSymbolStyleTriangle
                                color: "red"
                                size: 18
                            }
                        }

                        Component.onCompleted: {
                            // Create a new point feature, provide geometry and attribute values
                            const pointFeature = pointsTable.createFeature();
                            pointFeature.attributes.replaceAttribute("Place", "Current location");
                            const point1 = ArcGISRuntimeEnvironment.createObject("Point", {x: -79.497238, y: 8.849289, spatialReference: Factory.SpatialReference.createWgs84()});
                            pointFeature.geometry = point1;

                            // Add to the table
                            pointsTable.addFeature(pointFeature);
                        }
                    }

                    // Create a Point FeatureCollectionTable inside the FeatureCollection
                    FeatureCollectionTable {
                        id: linesTable

                        // define the schema of the table
                        geometryType: Enums.GeometryTypePolyline
                        spatialReference: SpatialReference { wkid: 4326 }
                        Field {
                            alias: "Boundary Name"
                            name: "Boundary"
                            length: 50
                            fieldType: Enums.FieldTypeText
                        }

                        // define the renderer
                        SimpleRenderer {
                            SimpleLineSymbol {
                                style: Enums.SimpleLineSymbolStyleDash
                                color: "green"
                                width: 3
                            }
                        }

                        Component.onCompleted: {
                            // Create a new polyline feature, provide geometry and attribute values
                            const lineFeature = linesTable.createFeature();
                            lineFeature.attributes.replaceAttribute("Boundary", "AManAPlanACanalPanama");
                            const point1 = ArcGISRuntimeEnvironment.createObject("Point", {x: -79.497238, y: 8.849289, spatialReference: Factory.SpatialReference.createWgs84()});
                            const point2 = ArcGISRuntimeEnvironment.createObject("Point", {x: -80.035568, y: 9.432302, spatialReference: Factory.SpatialReference.createWgs84()});
                            const lineBuilder = ArcGISRuntimeEnvironment.createObject("PolylineBuilder", {spatialReference: Factory.SpatialReference.createWgs84()});
                            lineBuilder.addPoint(point1);
                            lineBuilder.addPoint(point2);
                            lineFeature.geometry = lineBuilder.geometry;

                            // Add to the table
                            linesTable.addFeature(lineFeature);
                        }
                    }

                    // Create a Point FeatureCollectionTable inside the FeatureCollection
                    FeatureCollectionTable {
                        id: polygonTable

                        // define the schema of the table
                        geometryType: Enums.GeometryTypePolygon
                        spatialReference: SpatialReference { wkid: 4326 }
                        Field {
                            alias: "Area Name"
                            name: "Area"
                            length: 50
                            fieldType: Enums.FieldTypeText
                        }

                        // define the renderer
                        SimpleRenderer {
                            // fill
                            SimpleFillSymbol {
                                style: Enums.SimpleFillSymbolStyleDiagonalCross
                                color: "cyan"

                                // outline
                                SimpleLineSymbol {
                                    style: Enums.SimpleLineSymbolStyleSolid
                                    color: "blue"
                                    width: 2
                                }
                            }
                        }

                        Component.onCompleted: {
                            // Create a new point feature, provide geometry and attribute values
                            const polygonFeature = linesTable.createFeature();
                            polygonFeature.attributes.replaceAttribute("Area", "Restricted area");
                            const point1 = ArcGISRuntimeEnvironment.createObject("Point", {x: -79.497238, y: 8.849289, spatialReference: Factory.SpatialReference.createWgs84()});
                            const point2 = ArcGISRuntimeEnvironment.createObject("Point", {x: -79.337936, y: 8.638903, spatialReference: Factory.SpatialReference.createWgs84()});
                            const point3 = ArcGISRuntimeEnvironment.createObject("Point", {x: -79.11409, y: 8.895422, spatialReference: Factory.SpatialReference.createWgs84()});
                            const polygonBuilder = ArcGISRuntimeEnvironment.createObject("PolygonBuilder", {spatialReference: Factory.SpatialReference.createWgs84()});
                            polygonBuilder.addPoint(point1);
                            polygonBuilder.addPoint(point2);
                            polygonBuilder.addPoint(point3);
                            polygonFeature.geometry = polygonBuilder.geometry;

                            // Add to the table
                            polygonTable.addFeature(polygonFeature);
                        }
                    }
                }
            }

            // set initial extent
            ViewpointExtent {
                Envelope {
                    xMax: -8800611.655131537
                    xMin: -8917856.590171767
                    yMax: 1100327.8941287803
                    yMin: 903277.583136797
                    spatialReference: SpatialReference { wkid: 3857 }
                }
            }
        }
    }
}

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