Create and save KML file

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Construct a KML document and save it as a KMZ file.

Image of create and save KML file

Use case

If you need to create and save data on the fly, you can use KML to create points, lines, and polygons by sketching on the map, customizing the style, and serializing them as KML nodes in a KML Document. Once complete, you can share the KML data with others that are using a KML reading application, such as ArcGIS Earth.

How to use the sample

Tap on one of the buttons in the middle row to start adding a geometry. Tap on the map view to place vertices. Tap the "Complete Sketch" button to add the geometry to the KML document as a new KML placemark. Use the style interface to edit the style of the placemark. If you do not wish to set a style, tap the "Don't Apply Style" button. When you are finished adding KML nodes, tap on the "Save KMZ file" button to save the active KML document as a .kmz file on your system. Use the "Reset" button to clear the current KML document and start a new one.

How it works

Create a KmlDocument
Create a KmlDataset using the KmlDocument.
Create a KmlLayer using the KmlDataset and add it to Map.OperationalLayers.
Create Geometry using SketchEditor.
Project that Geometry to WGS84 using GeometryEngine.Project.
Create a KmlGeometry object using that projected Geometry.
Create a KmlPlacemark using the KmlGeometry.
Add the KmlPlacemark to the KmlDocument.
Set the KmlStyle for the KmlPlacemark.
When finished with adding KmlPlacemark nodes to the KmlDocument, save the KmlDocument to a file using the SaveAsAsync method.

Relevant API

GeometryEngine.Project
KmlDataset
KmlDocument
KmlGeometry
KmlLayer
KmlNode.SaveAsASync
KmlPlacemark
KmlStyle
SketchEditor

Sample Code

CreateAndSaveKmlFile.cs

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// 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.

using Android;
using Android.App;
using Android.Content;
using Android.Graphics;
using Android.OS;
using Android.Support.V4.App;
using Android.Support.V4.Content;
using Android.Views;
using Android.Widget;
using Esri.ArcGISRuntime.Geometry;
using Esri.ArcGISRuntime.Mapping;
using Esri.ArcGISRuntime.Ogc;
using Esri.ArcGISRuntime.UI;
using Esri.ArcGISRuntime.UI.Controls;
using System;
using System.Collections.Generic;
using System.IO;
using System.Net;
using Resource = ArcGISRuntime.Resource;

namespace ArcGISRuntimeXamarin.Samples.CreateAndSaveKmlFile
{
    [Activity(ConfigurationChanges = Android.Content.PM.ConfigChanges.Orientation | Android.Content.PM.ConfigChanges.ScreenSize)]
    [ArcGISRuntime.Samples.Shared.Attributes.Sample(
        name: "Create and save KML file",
        category: "Layers",
        description: "Construct a KML document and save it as a KMZ file.",
        instructions: "Tap on one of the buttons in the middle row to start adding a geometry. Tap on the map view to place vertices. Tap the \"Complete Sketch\" button to add the geometry to the KML document as a new KML placemark. Use the style interface to edit the style of the placemark. If you do not wish to set a style, tap the \"Don't Apply Style\" button. When you are finished adding KML nodes, tap on the \"Save KMZ file\" button to save the active KML document as a .kmz file on your system. Use the \"Reset\" button to clear the current KML document and start a new one.",
        tags: new[] { "KML", "KMZ", "Keyhole", "OGC" })]
    [ArcGISRuntime.Samples.Shared.Attributes.AndroidLayout("CreateAndSaveKmlFile.axml")]
    [ArcGISRuntime.Samples.Shared.Attributes.OfflineData()]
    public class CreateAndSaveKmlFile : Activity
    {
        // Hold references to the UI controls.
        private MapView _myMapView;
        private Button _addButton;
        private Button _saveButton;
        private Button _resetButton;
        private Button _completeButton;
        private Button _noStyleButton;
        private LinearLayout _buttonLayout;
        private LinearLayout _pickerLayout;
        private TextView _status;
        private TextView _styleText;
        private ListView _listView;
        private BaseAdapter _iconAdapter;
        private BaseAdapter _colorAdapter;

        private KmlDocument _kmlDocument;
        private KmlDataset _kmlDataset;
        private KmlLayer _kmlLayer;
        private KmlPlacemark _currentPlacemark;

        private List<string> _iconLinks;
        private List<Color> _colorList;

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

            Title = "Create and save KML file";

            CreateLayout();
            Initialize();
        }

        private void Initialize()
        {
            // Create the map.
            _myMapView.Map = new Map(BasemapStyle.ArcGISImageryStandard);

            // Set up a new kml document and kml layer.
            ResetKml();

            // Set the colors for the color picker.
            _colorList = new List<Color>()
            {
               Color.Blue, Color.Brown, Color.Gray, Color.Green, Color.Yellow, Color.Pink, Color.Purple, Color.Red, Color.Black
            };
            _colorAdapter = new ColorAdapter(this, _colorList);

            // Set the images for the point icon picker.
            _iconLinks = new List<string>()
            {
                "https://static.arcgis.com/images/Symbols/Shapes/BlueCircleLargeB.png",
                "https://static.arcgis.com/images/Symbols/Shapes/BlueDiamondLargeB.png",
                "https://static.arcgis.com/images/Symbols/Shapes/BluePin1LargeB.png",
                "https://static.arcgis.com/images/Symbols/Shapes/BluePin2LargeB.png",
                "https://static.arcgis.com/images/Symbols/Shapes/BlueSquareLargeB.png",
                "https://static.arcgis.com/images/Symbols/Shapes/BlueStarLargeB.png"
            };

            // Request permission to save a file.
            if (ContextCompat.CheckSelfPermission(this, Manifest.Permission.WriteExternalStorage) != Android.Content.PM.Permission.Granted)
            {
                ActivityCompat.RequestPermissions(this, new string[] { Manifest.Permission.WriteExternalStorage }, 1);
            }
        }

        private void ResetKml()
        {
            // Clear any existing layers from the map.
            _myMapView.Map.OperationalLayers.Clear();

            // Reset the most recently placed placemark.
            _currentPlacemark = null;

            // Create a new KML document.
            _kmlDocument = new KmlDocument() { Name = "KML Sample Document" };

            // Create a KML dataset using the KML document.
            _kmlDataset = new KmlDataset(_kmlDocument);

            // Create the KML layer using the KML dataset.
            _kmlLayer = new KmlLayer(_kmlDataset);

            // Add the KML layer to the map.
            _myMapView.Map.OperationalLayers.Add(_kmlLayer);
        }

        private void Add_Click(object sender, EventArgs e)
        {
            string[] options = new string[] { "Point", "Polyline", "Polygon" };

            // Create UI for terminal selection.
            AlertDialog.Builder builder = new AlertDialog.Builder(this);
            builder.SetItems(options, Draw);
            builder.SetCancelable(false);
            builder.Show();
        }

        private async void Draw(object sender, DialogClickEventArgs e)
        {
            try
            {
                // Hide the base UI and enable the complete button.
                _buttonLayout.Visibility = ViewStates.Invisible;
                _completeButton.Visibility = ViewStates.Visible;

                // Create variables for the sketch creation mode and color.
                SketchCreationMode creationMode;

                // Set the creation mode and UI based on which button called this method.
                switch (e.Which)
                {
                    case 0:
                        creationMode = SketchCreationMode.Point;
                        _status.Text = "Tap to add a point.";
                        //StyleText.Text = "Select an icon for the placemark.";
                        break;

                    case 1:
                        creationMode = SketchCreationMode.Polyline;
                        _status.Text = "Tap to add a vertex.";
                        //StyleText.Text = "Select a color for the placemark.";
                        break;

                    case 2:
                        creationMode = SketchCreationMode.Polygon;
                        _status.Text = "Tap to add a vertex.";
                        //StyleText.Text = "Select a color for the placemark.";
                        break;

                    default:
                        return;
                }

                // Get the user-drawn geometry.
                Geometry geometry = await _myMapView.SketchEditor.StartAsync(creationMode, true);

                // Project the geometry to WGS84 (WGS84 is required by the KML standard).
                Geometry projectedGeometry = GeometryEngine.Project(geometry, SpatialReferences.Wgs84);

                // Create a KmlGeometry using the new geometry.
                KmlGeometry kmlGeometry = new KmlGeometry(projectedGeometry, KmlAltitudeMode.ClampToGround);

                // Create a new placemark.
                _currentPlacemark = new KmlPlacemark(kmlGeometry);

                // Add the placemark to the KmlDocument.
                _kmlDocument.ChildNodes.Add(_currentPlacemark);

                // Choose whether to open the icon picker or color picker.
                if (creationMode == SketchCreationMode.Point) { OpenIconDialog(); }
                else { OpenColorDialog(); }
            }
            catch (ArgumentException)
            {
                new AlertDialog.Builder(this).SetMessage("Unsupported Geometry").SetTitle("Error").Show();
            }
            finally
            {
                // Reset the UI.
                _buttonLayout.Visibility = ViewStates.Visible;
                _completeButton.Visibility = ViewStates.Invisible;
                _status.Text = "";
            }
        }

        private void Complete_Click(object sender, EventArgs e)
        {
            try
            {
                // Finish the sketch.
                _myMapView.SketchEditor.CompleteCommand.Execute(null);
            }
            catch (ArgumentException)
            {
            }
        }

        private void OpenIconDialog()
        {
            // Create the icon adapter if it has not been created yet.
            if (_iconAdapter == null) { _iconAdapter = new IconAdapter(this, _iconLinks); }

            // Display the picker view.
            _listView.Adapter = _iconAdapter;
            _styleText.Text = "Select an icon.";
            _pickerLayout.Visibility = ViewStates.Visible;
            _listView.ItemClick += IconSelected;
        }

        private void IconSelected(object sender, AdapterView.ItemClickEventArgs e)
        {
            // Set the style of the placemark.
            _currentPlacemark.Style = new KmlStyle();
            _currentPlacemark.Style.IconStyle = new KmlIconStyle(new KmlIcon(new Uri(_iconLinks[(int)e.Id])), 1.0);

            // Reset the UI.
            _pickerLayout.Visibility = ViewStates.Invisible;
            _listView.ItemClick -= IconSelected;
        }

        private void OpenColorDialog()
        {
            // Display the picker view.
            _listView.Adapter = _colorAdapter;
            _styleText.Text = "Select a color.";
            _pickerLayout.Visibility = ViewStates.Visible;
            _listView.ItemClick += ColorSelected;
        }

        private void ColorSelected(object sender, AdapterView.ItemClickEventArgs e)
        {
            // Convert the selected Android color into a System.Drawing.Color.
            Color androidColor = _colorList[e.Position];
            System.Drawing.Color systemColor = System.Drawing.Color.FromArgb(androidColor.R, androidColor.G, androidColor.B);

            // Create a new style for the placemark.
            _currentPlacemark.Style = new KmlStyle();

            // Check the graphic type of the placemark.
            if (_currentPlacemark.GraphicType == KmlGraphicType.Polyline)
            {
                // Set the line style.
                _currentPlacemark.Style.LineStyle = new KmlLineStyle(systemColor, 8);
            }
            else if (_currentPlacemark.GraphicType == KmlGraphicType.Polygon)
            {
                // Set the polygon style.
                _currentPlacemark.Style.PolygonStyle = new KmlPolygonStyle(systemColor);
                _currentPlacemark.Style.PolygonStyle.IsFilled = true;
                _currentPlacemark.Style.PolygonStyle.IsOutlined = false;
            }

            // Reset the UI.
            _pickerLayout.Visibility = ViewStates.Invisible;
            _listView.ItemClick -= ColorSelected;
        }

        private void No_Style_Click(object sender, EventArgs e)
        {
            // Reset the UI.
            _pickerLayout.Visibility = ViewStates.Invisible;
            _listView.ItemClick -= IconSelected;
            _listView.ItemClick -= ColorSelected;
        }

        private async void Save_Click(object sender, EventArgs e)
        {
            // Determine where to save your file
            string filePath = System.IO.Path.Combine(ApplicationContext.GetExternalFilesDir(null).AbsolutePath, "sampledata.kmz");

            // Check if the user can save their file.
            if (ContextCompat.CheckSelfPermission(this, Manifest.Permission.WriteExternalStorage) != Android.Content.PM.Permission.Granted)
            {
                ActivityCompat.RequestPermissions(this, new string[] { Manifest.Permission.WriteExternalStorage }, 1);
            }
            else
            {
                using (Stream stream = new FileStream(filePath, FileMode.OpenOrCreate, FileAccess.Write, FileShare.None))
                {
                    // Write the KML document to the stream of the file.
                    await _kmlDocument.WriteToAsync(stream);
                }
                new AlertDialog.Builder(this).SetMessage("File saved to " + filePath).SetTitle("Success!").Show();
            }
        }

        private void Reset_Click(object sender, EventArgs e)
        {
            ResetKml();
        }

        private void CreateLayout()
        {
            // Load the layout from the axml resource.
            SetContentView(Resource.Layout.CreateAndSaveKmlFile);

            _myMapView = FindViewById<MapView>(Resource.Id.MapView);
            _addButton = FindViewById<Button>(Resource.Id.addButton);
            _saveButton = FindViewById<Button>(Resource.Id.saveButton);
            _resetButton = FindViewById<Button>(Resource.Id.resetButton);
            _completeButton = FindViewById<Button>(Resource.Id.completeButton);
            _noStyleButton = FindViewById<Button>(Resource.Id.noStyleButton);
            _buttonLayout = FindViewById<LinearLayout>(Resource.Id.linearLayout);
            _pickerLayout = FindViewById<LinearLayout>(Resource.Id.PickerUI);
            _status = FindViewById<TextView>(Resource.Id.statusLabel);
            _styleText = FindViewById<TextView>(Resource.Id.styleText);
            _listView = FindViewById<ListView>(Resource.Id.listView);

            // Add listeners for all of the buttons.
            _addButton.Click += Add_Click;
            _saveButton.Click += Save_Click;
            _resetButton.Click += Reset_Click;
            _completeButton.Click += Complete_Click;
            _noStyleButton.Click += No_Style_Click;
        }
    }

    // Adapter to display icons in a ListView.
    public class IconAdapter : BaseAdapter<Bitmap>
    {
        public List<Bitmap> iconList;
        private Context context;

        public IconAdapter(Context context, List<string> list)
        {
            this.context = context;
            iconList = new List<Bitmap>();

            foreach (string link in list)
            {
                Bitmap imageBitmap;
                imageBitmap = BitmapFactory.DecodeStream(WebRequest.Create(link).GetResponse().GetResponseStream());
                iconList.Add(imageBitmap);
            }
        }

        public override Bitmap this[int position] => iconList[position];

        public override int Count => iconList.Count;

        public override long GetItemId(int position)
        {
            return position;
        }

        public override View GetView(int position, View convertView, ViewGroup parent)
        {
            // Create the image.
            ImageView image = new ImageView(this.context);
            image.SetImageBitmap(iconList[position]);
            image.SetMinimumHeight(150);
            image.SetMinimumWidth(150);

            // Create the layout.
            LinearLayout layout = new LinearLayout(context) { Orientation = Orientation.Horizontal };
            layout.AddView(image);
            layout.SetMinimumHeight(150);
            return layout;
        }
    }

    // Adapter to display color options in a ListView.
    public class ColorAdapter : BaseAdapter<Color>
    {
        public List<Color> colorList;
        private Context context;

        public ColorAdapter(Context context, List<Color> list)
        {
            this.context = context;
            colorList = list;
        }

        public override Color this[int position] => throw new NotImplementedException();

        public override int Count => colorList.Count;

        public override long GetItemId(int position)
        {
            return position;
        }

        public override View GetView(int position, View convertView, ViewGroup parent)
        {
            // Create a simple layout for the color.
            LinearLayout layout = new LinearLayout(context) { Orientation = Orientation.Horizontal };
            layout.SetMinimumHeight(150);
            layout.SetBackgroundColor(colorList[position]);
            return layout;
        }
    }
}