Create feature collection layer (Portal item)

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Create a feature collection layer from a portal item.

Image of create feature collection layer portal item

Use case

Feature collection layers are often used to hold features with mixed geometry or unstructured data. You can display feature collections stored in a Portal, which are often used for showing content from a CSV or map notes.

How to use the sample

The feature collection is loaded from the Portal item when the sample starts.

How it works

  1. Create a Portal.
  2. Create the PortalItem, referring to the portal and an item ID.
  3. Verify that the item represents a feature collection.
  4. Create a FeatureCollection from the item.
  5. Create a FeatureCollectionLayer, referring to the feature collection.
  6. Add the feature collection layer to the map's OperationalLayers collection.

Relevant API

  • FeatureCollection
  • FeatureCollectionLayer
  • Portal
  • PortalItem

About the data

The sample uses a sample layer depicting world populations.

Tags

collection, feature collection, feature collection layer, id, item, map notes, portal

Sample Code

FeatureCollectionLayerFromPortal.cs
                                                                                                                                                
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// Copyright 2018 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.

using Android.App;
using Android.OS;
using Android.Widget;
using Esri.ArcGISRuntime.Data;
using Esri.ArcGISRuntime.Mapping;
using Esri.ArcGISRuntime.Portal;
using Esri.ArcGISRuntime.UI.Controls;
using System;

namespace ArcGISRuntime.Samples.FeatureCollectionLayerFromPortal
{
    [Activity (ConfigurationChanges=Android.Content.PM.ConfigChanges.Orientation | Android.Content.PM.ConfigChanges.ScreenSize)]
    [ArcGISRuntime.Samples.Shared.Attributes.Sample(
        name: "Create feature collection layer (Portal item)",
        category: "Layers",
        description: "Create a feature collection layer from a portal item.",
        instructions: "The feature collection is loaded from the Portal item when the sample starts.",
        tags: new[] { "collection", "feature collection", "feature collection layer", "id", "item", "map notes", "portal" })]
    public class FeatureCollectionLayerFromPortal : Activity
    {
        // Hold a reference to the map view.
        private MapView _myMapView;

        // Store a text box control with a portal item Id.
        private EditText _portalItemIdEditText;

        // Default portal item Id to load features from.
        private const string FeatureCollectionItemId = "32798dfad17942858d5eef82ee802f0b";

        protected override void OnCreate(Bundle bundle)
        {
            base.OnCreate(bundle);

            Title = "Create a feature collection layer from a portal item";

            // Create the UI.
            CreateLayout();

            // Initialize the app.
            Initialize();
        }

        private void Initialize()
        {
            // Add a default value for the portal item Id.
            _portalItemIdEditText.Text = FeatureCollectionItemId;

            // Create a new map with the oceans basemap and add it to the map view.
            _myMapView.Map = new Map(BasemapStyle.ArcGISOceans);
        }

        private async void OpenFeaturesFromArcGISOnline(string itemId)
        {
            try
            {
                // Open a portal item containing a feature collection.
                ArcGISPortal portal = await ArcGISPortal.CreateAsync();
                PortalItem collectionItem = await PortalItem.CreateAsync(portal, itemId);

                // Verify that the item is a feature collection.
                if (collectionItem.Type == PortalItemType.FeatureCollection)
                {
                    // Create a new FeatureCollection from the item.
                    FeatureCollection featureCollection = new FeatureCollection(collectionItem);

                    // Create a layer to display the collection and add it to the map as an operational layer.
                    FeatureCollectionLayer featureCollectionLayer = new FeatureCollectionLayer(featureCollection)
                    {
                        Name = collectionItem.Title
                    };

                    _myMapView.Map.OperationalLayers.Add(featureCollectionLayer);
                }
                else
                {
                    AlertDialog.Builder alertBuilder = new AlertDialog.Builder(this);
                    alertBuilder.SetTitle("Feature Collection");
                    alertBuilder.SetMessage("Portal item with ID '" + itemId + "' is not a feature collection.");
                    alertBuilder.Show();
                }
            }
            catch (Exception ex)
            {
                AlertDialog.Builder alertBuilder = new AlertDialog.Builder(this);
                alertBuilder.SetTitle("Error");
                alertBuilder.SetMessage("Unable to open item with ID '" + itemId + "': " + ex.Message);
                alertBuilder.Show();
            }
        }

        private void OpenPortalFeatureCollectionClick(object sender, EventArgs e)
        {
            // Get the portal item Id from the user.
            string collectionItemId = _portalItemIdEditText.Text.Trim();

            // Make sure an Id was entered.
            if (String.IsNullOrEmpty(collectionItemId))
            {
                AlertDialog.Builder alertBuilder = new AlertDialog.Builder(this);
                alertBuilder.SetTitle("Feature Collection ID");
                alertBuilder.SetMessage("Please enter a portal item ID");
                alertBuilder.Show();
                return;
            }

            // Call a function to add the feature collection from the specified portal item.
            OpenFeaturesFromArcGISOnline(collectionItemId);
        }

        private void CreateLayout()
        {
            // Create a new layout.
            LinearLayout layout = new LinearLayout(this) { Orientation = Orientation.Vertical };

            // Create a button to load features from a portal item, add it to the layout.
            Button loadFeaturesButton = new Button(this) { Text = "Load features" };
            loadFeaturesButton.Click += OpenPortalFeatureCollectionClick;
            layout.AddView(loadFeaturesButton);

            // Create an edit text for the user to enter a portal item Id.
            _portalItemIdEditText = new EditText(this)
            {
                Hint = "Portal Item Id"
            };
            layout.AddView(_portalItemIdEditText);

            // Add the map view to the layout.
            _myMapView = new MapView(this);
            layout.AddView(_myMapView);

            // Show the layout in the app.
            SetContentView(layout);
        }
    }
}

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