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

  1. Create a FeatureCollectionLayer using a new feature collection, FeatureCollectionLayer(featureCollection)
  2. Add the feature collection layer to the map, Map::operationalLayers()::append(featureCollectionLayer).
  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()::append(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.cppFeature_Collection_Layer.cppFeature_Collection_Layer.hFeature_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]

#ifdef PCH_BUILD
#include "pch.hpp"
#endif // PCH_BUILD

#include "Feature_Collection_Layer.h"

#include "Map.h"
#include "MapQuickView.h"
#include "Viewpoint.h"
#include "Envelope.h"
#include "Basemap.h"
#include "Feature.h"
#include "FeatureCollection.h"
#include "FeatureCollectionLayer.h"
#include "FeatureCollectionTable.h"
#include "Field.h"
#include "Point.h"
#include "Polygon.h"
#include "PolygonBuilder.h"
#include "Polyline.h"
#include "PolylineBuilder.h"
#include "SpatialReference.h"
#include "SimpleRenderer.h"
#include "SimpleMarkerSymbol.h"
#include "SimpleFillSymbol.h"
#include "SimpleLineSymbol.h"

using namespace Esri::ArcGISRuntime;

Feature_Collection_Layer::Feature_Collection_Layer(QQuickItem* parent /* = nullptr */):
  QQuickItem(parent)
{
}

Feature_Collection_Layer::~Feature_Collection_Layer() = default;

void Feature_Collection_Layer::init()
{
  qmlRegisterType<MapQuickView>("Esri.Samples", 1, 0, "MapView");
  qmlRegisterType<Feature_Collection_Layer>("Esri.Samples", 1, 0, "Feature_Collection_LayerSample");
}

void Feature_Collection_Layer::componentComplete()
{
  QQuickItem::componentComplete();

  // find QML MapView component
  m_mapView = findChild<MapQuickView*>("mapView");
  m_mapView->setWrapAroundMode(WrapAroundMode::Disabled);

  // Create a map using the topographic basemap
  m_map = new Map(BasemapStyle::ArcGISOceans, this);
  m_map->setInitialViewpoint(Viewpoint(Envelope(-8917856.590171767, 903277.583136797, -8800611.655131537, 1100327.8941287803, SpatialReference(102100))));

  // Set map to map view
  m_mapView->setMap(m_map);

  // Create FeatureCollection and FeatureCollectionLayer
  m_featureCollection = new FeatureCollection(this);
  m_featureCollectionLayer = new FeatureCollectionLayer(m_featureCollection, this);

  // Add the Layer to the Map
  m_map->operationalLayers()->append(m_featureCollectionLayer);

  // Create the FeatureCollectionTables
  createPointTable();
  createPolylineTable();
  createPolygonTable();
}

void Feature_Collection_Layer::createPointTable()
{
  // Define the schema
  QList<Field> pointFields;
  Field placeField = Field::createText("Place", "Place Name", 50);
  pointFields.append(placeField);

  // Create the table
  FeatureCollectionTable* pointsTable =  new FeatureCollectionTable(pointFields, GeometryType::Point, SpatialReference(4326), this);

  // Define the renderer
  SimpleMarkerSymbol* sms = new SimpleMarkerSymbol(SimpleMarkerSymbolStyle::Triangle, QColor("red"), 18.0, this);
  SimpleRenderer* renderer = new SimpleRenderer(sms, this);
  pointsTable->setRenderer(renderer);

  // Add the table to the collection
  m_featureCollection->tables()->append(pointsTable);

  // Add features to the table
  Point pt1(-79.497238, 8.849289, SpatialReference::wgs84());
  addPointToTable("Place", "Current location", pt1, pointsTable);
}

void Feature_Collection_Layer::createPolylineTable()
{
  // Define the schema
  QList<Field> lineFields;
  Field boundaryField = Field::createText("Boundary", "Boundary Name", 50);
  lineFields.append(boundaryField);

  // Create the table
  FeatureCollectionTable* linesTable =  new FeatureCollectionTable(lineFields, GeometryType::Polyline, SpatialReference(4326), this);

  // Define the renderer
  SimpleLineSymbol* sls = new SimpleLineSymbol(SimpleLineSymbolStyle::Dash, QColor("green"), 3.0, this);
  SimpleRenderer* renderer = new SimpleRenderer(sls, this);
  linesTable->setRenderer(renderer);

  // Add the table to the collection
  m_featureCollection->tables()->append(linesTable);

  // Add features to the table
  Point pt1(-79.497238, 8.849289, SpatialReference::wgs84());
  Point pt2(-80.035568, 9.432302, SpatialReference::wgs84());
  QList<Point> points { pt1, pt2 };
  addPolylineToTable("Boundary", "AManAPlanACanalPanama", points, linesTable);
}

void Feature_Collection_Layer::createPolygonTable()
{
  // Define the schema
  QList<Field> polyFields;
  Field areaField = Field::createText("Area", "Area Name", 50);
  polyFields.append(areaField);

  // Create the table
  FeatureCollectionTable* polysTable =  new FeatureCollectionTable(polyFields, GeometryType::Polygon, SpatialReference(4326), this);

  // Define the renderer
  SimpleLineSymbol* sls = new SimpleLineSymbol(SimpleLineSymbolStyle::Solid, QColor("blue"), 2.0, this);
  SimpleFillSymbol* sfs = new SimpleFillSymbol(SimpleFillSymbolStyle::DiagonalCross, QColor("cyan"), sls, this);
  SimpleRenderer* renderer = new SimpleRenderer(sfs, this);
  polysTable->setRenderer(renderer);

  // Add the table to the collection
  m_featureCollection->tables()->append(polysTable);

  // Add features to the table
  const Point pt1(-79.497238, 8.849289, SpatialReference::wgs84());
  const Point pt2(-79.337936, 8.638903, SpatialReference::wgs84());
  const Point pt3(-79.11409, 8.895422, SpatialReference::wgs84());
  const QList<Point> points{ pt1, pt2, pt3 };
  addPolygonToTable("Area", "Restricted area", points, polysTable);
}

void Feature_Collection_Layer::addPointToTable(QString attrName, QString attrValue, Point point, FeatureCollectionTable* table)
{
  // Create the new feature
  Feature* feature = table->createFeature(this);
  feature->attributes()->replaceAttribute(attrName, attrValue);
  feature->setGeometry(point);

  // Add the feature to the table
  table->addFeature(feature);
}

void Feature_Collection_Layer::addPolylineToTable(QString attrName, QString attrValue, QList<Point> points, FeatureCollectionTable* table)
{
  // Create the new feature
  Feature* feature = table->createFeature(this);
  feature->attributes()->replaceAttribute(attrName, attrValue);
  PolylineBuilder* builder = new PolylineBuilder(SpatialReference(4326), this);
  for (const Point& pt : points)
  {
    builder->addPoint(pt);
  }
  feature->setGeometry(builder->toGeometry());

  // Add the feature to the table
  table->addFeature(feature);
}

void Feature_Collection_Layer::addPolygonToTable(QString attrName, QString attrValue, QList<Point> points, FeatureCollectionTable* table)
{
  // Create the new feature
  Feature* feature = table->createFeature(this);
  feature->attributes()->replaceAttribute(attrName, attrValue);
  PolygonBuilder* builder = new PolygonBuilder(SpatialReference(4326), this);
  for (const Point& pt : points)
  {
    builder->addPoint(pt);
  }
  feature->setGeometry(builder->toGeometry());

  // Add the feature to the table
  table->addFeature(feature);
}

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