Geodesic operations

<UserControl x:Class="ArcGIS.WPF.Samples.GeodesicOperations.GeodesicOperations"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:esri="http://schemas.esri.com/arcgis/runtime/2013">
    <Grid>
        <esri:MapView x:Name="MyMapView" />
        <Border Style="{StaticResource BorderStyle}">
            <TextBlock x:Name="ResultsLabel"
                       FontWeight="SemiBold"
                       Text="Tap to set an end point."
                       TextAlignment="Center" />
        </Border>
    </Grid>
</UserControl>

// 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 Esri.ArcGISRuntime.Geometry;
using Esri.ArcGISRuntime.Mapping;
using Esri.ArcGISRuntime.Symbology;
using Esri.ArcGISRuntime.UI;
using Esri.ArcGISRuntime.UI.Controls;

namespace ArcGIS.WPF.Samples.GeodesicOperations
{
    [ArcGIS.Samples.Shared.Attributes.Sample(
        name: "Geodesic operations",
        category: "Geometry",
        description: "Calculate a geodesic path between two points and measure its distance.",
        instructions: "Click anywhere on the map. A line graphic will display the geodesic line between the two points. In addition, text that indicates the geodesic distance between the two points will be updated. Click elsewhere and a new line will be created.",
        tags: new[] { "densify", "distance", "geodesic", "geodetic" })]
    public partial class GeodesicOperations
    {
        // Hold references to the graphics and start point.
        private Graphic _startLocationGraphic;
        private Graphic _endLocationGraphic;
        private Graphic _pathGraphic;
        private MapPoint _startPoint;

        public GeodesicOperations()
        {
            InitializeComponent();

            // Create the map, set the initial extent, and add the original point graphic.
            Initialize();
        }

        private void Initialize()
        {
            MyMapView.Map = new Map(BasemapStyle.ArcGISImageryStandard);

            // Create the graphics overlay and add it to the map view.
            GraphicsOverlay graphicsOverlay = new GraphicsOverlay();
            MyMapView.GraphicsOverlays.Add(graphicsOverlay);

            // Add a graphic at JFK to serve as the origin.
            _startPoint = new MapPoint(-73.7781, 40.6413, SpatialReferences.Wgs84);
            SimpleMarkerSymbol startMarker = new SimpleMarkerSymbol(SimpleMarkerSymbolStyle.Circle, System.Drawing.Color.Blue, 10);
            _startLocationGraphic = new Graphic(_startPoint, startMarker);

            // Create the graphic for the destination.
            _endLocationGraphic = new Graphic
            {
                Symbol = startMarker
            };

            // Create the graphic for the path.
            _pathGraphic = new Graphic
            {
                Symbol = new SimpleLineSymbol(SimpleLineSymbolStyle.Dash, System.Drawing.Color.Blue, 5)
            };

            // Add the graphics to the overlay.
            graphicsOverlay.Graphics.Add(_startLocationGraphic);
            graphicsOverlay.Graphics.Add(_endLocationGraphic);
            graphicsOverlay.Graphics.Add(_pathGraphic);

            // Update end location when the user taps.
            MyMapView.GeoViewTapped += MyMapViewOnGeoViewTapped;
        }

        private void MyMapViewOnGeoViewTapped(object sender, GeoViewInputEventArgs geoViewInputEventArgs)
        {
            // Get the tapped point, projected to WGS84.
            MapPoint destination = (MapPoint)geoViewInputEventArgs.Location.Project(SpatialReferences.Wgs84);

            // Update the destination graphic.
            _endLocationGraphic.Geometry = destination;

            // Get the points that define the route polyline.
            PointCollection polylinePoints = new PointCollection(SpatialReferences.Wgs84)
            {
                (MapPoint)_startLocationGraphic.Geometry,
                destination
            };

            // Create the polyline for the two points.
            Polyline routeLine = new Polyline(polylinePoints);

            // Densify the polyline to show the geodesic curve.
            Geometry pathGeometry = routeLine.DensifyGeodetic(1, LinearUnits.Kilometers, GeodeticCurveType.Geodesic);

            // Apply the curved line to the path graphic.
            _pathGraphic.Geometry = pathGeometry;

            // Calculate and show the distance.
            GeodeticDistanceResult geodeticDistance = _startPoint.DistanceGeodetic(destination, LinearUnits.Kilometers,AngularUnits.Grads,GeodeticCurveType.Geodesic);
            ResultsLabel.Text = string.Format("{0} kilometers", (int)geodeticDistance.Distance);
        }
    }
}