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GeoElement Class

A marker interface implemented by objects that can be returned from an identify operation.
Inheritance Hierarchy
SystemObject
  Esri.ArcGISRuntime.DataGeoElement
    More...

Namespace:  Esri.ArcGISRuntime.Data
Assembly:  Esri.ArcGISRuntime (in Esri.ArcGISRuntime.dll) Version: 100.9.0.0
Syntax
C#
public abstract class GeoElement

The GeoElement type exposes the following members.

Properties
  NameDescription
Public propertyCode exampleAttributes
Gets the attributes of this GeoElement as a collection of name/value pairs.
Public propertyCode exampleGeometry
Gets the geometry of a GeoElement.
Top
Examples

Android

Example Name: IdentifyRasterCell

Get the cell value of a local raster at the tapped location and display the result in a callout.

Code example screen shot.

C#
// Copyright 2020 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 ArcGISRuntime.Samples.Managers;
using Esri.ArcGISRuntime.Data;
using Esri.ArcGISRuntime.Mapping;
using Esri.ArcGISRuntime.Rasters;
using Esri.ArcGISRuntime.UI;
using Esri.ArcGISRuntime.UI.Controls;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ArcGISRuntimeXamarin.Samples.IdentifyRasterCell
{
    [Activity(ConfigurationChanges = Android.Content.PM.ConfigChanges.Orientation | Android.Content.PM.ConfigChanges.ScreenSize)]
    [ArcGISRuntime.Samples.Shared.Attributes.Sample(
        name: "Identify raster cell",
        category: "Layers",
        description: "Get the cell value of a local raster at the tapped location and display the result in a callout.",
        instructions: "Tap or move your cursor over an area of the raster to identify a raster cell and display it's attributes in a callout.",
        tags: new[] { "NDVI", "band", "cell", "cell value", "continuous", "discrete", "identify", "pixel", "pixel value", "raster" })]
    [ArcGISRuntime.Samples.Shared.Attributes.OfflineData("b5f977c78ec74b3a8857ca86d1d9b318")]
    public class IdentifyRasterCell : Activity
    {
        // Hold references to the UI controls.
        private MapView _myMapView;

        // Raster layer to display raster data on the map.
        private RasterLayer _rasterLayer;

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

            Title = "Identify raster cell";

            CreateLayout();
            Initialize();
        }

        private async void Initialize()
        {
            // Define a new map with Wgs84 Spatial Reference.
            var map = new Map(BasemapType.Oceans, latitude: -34.1, longitude: 18.6, levelOfDetail: 9);

            // Get the file name for the raster.
            string filepath = DataManager.GetDataFolder("b5f977c78ec74b3a8857ca86d1d9b318", "SA_EVI_8Day_03May20.tif");

            // Load the raster file.
            var raster = new Raster(filepath);

            // Initialize the raster layer.
            _rasterLayer = new RasterLayer(raster);

            // Add the raster layer to the map.
            map.OperationalLayers.Add(_rasterLayer);

            // Add map to the map view.
            _myMapView.Map = map;

            try
            {
                // Wait for the layer to load.
                await _rasterLayer.LoadAsync();

                // Set the viewpoint.
                await _myMapView.SetViewpointGeometryAsync(_rasterLayer.FullExtent);
            }
            catch (Exception ex)
            {
                new AlertDialog.Builder(this).SetMessage(ex.Message).SetTitle(ex.GetType().Name).Show();
            }

            // Listen for mouse movement to start the identify operation.
            _myMapView.GeoViewTapped += MapTapped;
        }

        private async void MapTapped(object sender, GeoViewInputEventArgs e)
        {
            try
            {
                // Get the result for where the user tapped on the raster layer.
                IdentifyLayerResult identifyResult = await _myMapView.IdentifyLayerAsync(_rasterLayer, e.Position, 1, false, 1);

                // If no cell was identified, dismiss the callout.
                if (!identifyResult.GeoElements.Any())
                {
                    _myMapView.DismissCallout();
                    return;
                }

                // Create a StringBuilder to display information to the user.
                var stringBuilder = new StringBuilder();

                // Get the identified raster cell.
                GeoElement cell = identifyResult.GeoElements.First();

                // Loop through the attributes (key/value pairs).
                foreach (KeyValuePair<string, object> keyValuePair in cell.Attributes)
                {
                    // Add the key/value pair to the string builder.
                    stringBuilder.AppendLine($"{keyValuePair.Key}: {keyValuePair.Value}");
                }

                // Get the x and y values of the cell.
                double x = cell.Geometry.Extent.XMin;
                double y = cell.Geometry.Extent.YMin;

                // Add the X & Y coordinates where the user clicked raster cell to the string builder.
                stringBuilder.AppendLine($"X: {Math.Round(x, 4)}\nY: {Math.Round(y, 4)}");

                // Create a callout using the string.
                var definition = new CalloutDefinition(string.Empty, stringBuilder.ToString());

                // Display the call out in the map view.
                _myMapView.ShowCalloutAt(e.Location, definition);
            }
            catch (Exception ex)
            {
                new AlertDialog.Builder(this).SetMessage(ex.Message).SetTitle(ex.GetType().Name).Show();
            }
        }

        private void CreateLayout()
        {
            // Create a new vertical layout for the app.
            var layout = new LinearLayout(this) { Orientation = Orientation.Vertical };

            // Add instructions label to layout.
            var instructions = new TextView(this) { Text = "Tap to identify raster cell." };
            layout.AddView(instructions);

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

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

        protected override void OnDestroy()
        {
            base.OnDestroy();

            // Unhook event handlers.
            _myMapView.GeoViewTapped -= MapTapped;
        }
    }
}
Examples

Xamarin Forms Android

Example Name: IdentifyRasterCell

Get the cell value of a local raster at the tapped location and display the result in a callout.

Code example screen shot.

C#
// Copyright 2020 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 ArcGISRuntime.Samples.Managers;
using Esri.ArcGISRuntime.Data;
using Esri.ArcGISRuntime.Mapping;
using Esri.ArcGISRuntime.Rasters;
using Esri.ArcGISRuntime.UI;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Xamarin.Forms;

namespace ArcGISRuntimeXamarin.Samples.IdentifyRasterCell
{
    [ArcGISRuntime.Samples.Shared.Attributes.Sample(
        name: "Identify raster cell",
        category: "Layers",
        description: "Get the cell value of a local raster at the tapped location and display the result in a callout.",
        instructions: "Tap or move your cursor over an area of the raster to identify a raster cell and display it's attributes in a callout.",
        tags: new[] { "NDVI", "band", "cell", "cell value", "continuous", "discrete", "identify", "pixel", "pixel value", "raster" })]
    [ArcGISRuntime.Samples.Shared.Attributes.OfflineData("b5f977c78ec74b3a8857ca86d1d9b318")]
    public partial class IdentifyRasterCell : ContentPage, IDisposable
    {
        // Raster layer to display raster data on the map.
        private RasterLayer _rasterLayer;

        public IdentifyRasterCell()
        {
            InitializeComponent();
            Initialize();
        }

        private async void Initialize()
        {
            // Define a new map with Wgs84 Spatial Reference.
            var map = new Map(BasemapType.Oceans, latitude: -34.1, longitude: 18.6, levelOfDetail: 9);

            // Get the file name for the raster.
            string filepath = DataManager.GetDataFolder("b5f977c78ec74b3a8857ca86d1d9b318", "SA_EVI_8Day_03May20.tif");

            // Load the raster file.
            var raster = new Raster(filepath);

            // Initialize the raster layer.
            _rasterLayer = new RasterLayer(raster);

            // Add the raster layer to the map.
            map.OperationalLayers.Add(_rasterLayer);

            // Add map to the map view.
            MyMapView.Map = map;

            try
            {
                // Wait for the layer to load.
                await _rasterLayer.LoadAsync();

                // Set the viewpoint.
                await MyMapView.SetViewpointGeometryAsync(_rasterLayer.FullExtent);
            }
            catch (Exception ex)
            {
                await Application.Current.MainPage.DisplayAlert(ex.GetType().Name, ex.Message, "OK");
            }

            // Listen for mouse movement to start the identify operation.
            MyMapView.GeoViewTapped += MapTapped;
        }

        private async void MapTapped(object sender, Esri.ArcGISRuntime.Xamarin.Forms.GeoViewInputEventArgs e)
        {
            try
            {
                // Get the result for where the user tapped on the raster layer.
                IdentifyLayerResult identifyResult = await MyMapView.IdentifyLayerAsync(_rasterLayer, e.Position, 1, false, 1);

                // If no cell was identified, dismiss the callout.
                if (!identifyResult.GeoElements.Any())
                {
                    MyMapView.DismissCallout();
                    return;
                }

                // Create a StringBuilder to display information to the user.
                var stringBuilder = new StringBuilder();

                // Get the identified raster cell.
                GeoElement cell = identifyResult.GeoElements.First();

                // Loop through the attributes (key/value pairs).
                foreach (KeyValuePair<string, object> keyValuePair in cell.Attributes)
                {
                    // Add the key/value pair to the string builder.
                    stringBuilder.AppendLine($"{keyValuePair.Key}: {keyValuePair.Value}");
                }

                // Get the x and y values of the cell.
                double x = cell.Geometry.Extent.XMin;
                double y = cell.Geometry.Extent.YMin;

                // Add the X & Y coordinates where the user clicked raster cell to the string builder.
                stringBuilder.AppendLine($"X: {Math.Round(x, 4)}\nY: {Math.Round(y, 4)}");

                // Create a callout using the string.
#if __IOS__
                var definition = new CalloutDefinition(string.Empty, stringBuilder.ToString().Replace("\n", " "));
#else
                var definition = new CalloutDefinition(string.Empty, stringBuilder.ToString());
#endif

                // Display the call out in the map view.
                MyMapView.ShowCalloutAt(e.Location, definition);
            }
            catch (Exception ex)
            {
                await Application.Current.MainPage.DisplayAlert(ex.GetType().Name, ex.Message, "OK");
            }
        }

        public void Dispose()
        {
            MyMapView.GeoViewTapped -= MapTapped;
        }
    }
}
XAML
<ContentPage
    x:Class="ArcGISRuntimeXamarin.Samples.IdentifyRasterCell.IdentifyRasterCell"
    xmlns="http://xamarin.com/schemas/2014/forms"
    xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
    xmlns:esriUI="clr-namespace:Esri.ArcGISRuntime.Xamarin.Forms;assembly=Esri.ArcGISRuntime.Xamarin.Forms"
    xmlns:resources="clr-namespace:Forms.Resources">
    <RelativeLayout>
        <esriUI:MapView
            x:Name="MyMapView"
            BindingContext="{x:Reference Name=ResponsiveFormContainer}"
            Style="{StaticResource MapWithFormStyle}" />
        <resources:ResponsiveFormContainer x:Name="ResponsiveFormContainer">
            <Label
                Grid.Row="1"
                Grid.Column="1"
                Text="Tap to identify raster cell." />
        </resources:ResponsiveFormContainer>
    </RelativeLayout>
</ContentPage>
See Also
Inheritance Hierarchy
Additional Examples
Hyperlink to ExampleDescription
Animate3DGraphicAn `OrbitGeoElementCameraController` follows a graphic while the graphic's position and rotation are animated.
ChooseCameraControllerControl the behavior of the camera in a scene.
DeleteFeaturesDelete features from an online feature service.
EditFeatureAttachmentsAdd, delete, and download attachments for features from a service.
IdentifyKmlFeaturesShow a callout with formatted content for a KML feature.
IdentifyLayersIdentify features in all layers in a map. MapView supports identifying features across multiple layers. Because some layer types have sublayers, the sample recursively counts results for sublayers within each layer.
IdentifyRasterCellGet the cell value of a local raster at the tapped location and display the result in a callout.
LineOfSightGeoElementShow a line of sight between two moving objects.
ListRelatedFeaturesList features related to the selected feature.
OfflineGeocodeGeocode addresses to locations and reverse geocode locations to addresses offline.
ReverseGeocodeUse an online service to find the address for a tapped point.
SceneLayerSelectionIdentify features in a scene to select.
SelectEncFeaturesSelect features in an ENC layer.
ShowPopupShow predefined popups from a web map.
TraceUtilityNetworkDiscover connected features in a utility network using connected, subnetwork, upstream, and downstream traces.
UpdateAttributesUpdate feature attributes in an online feature service.
UpdateGeometriesUpdate a feature's location in an online feature service.
UseDistanceCompositeSymChange a graphic's symbol based on the camera's proximity to it.
ViewshedGeoElementAnalyze the viewshed for an object (GeoElement) in a scene.
WmsIdentifyIdentify features in a WMS layer and display the associated popup content.