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GeometryEngineLengthGeodetic Method

Gets the geodesic length for the Geometry passed in. Geodesic length is calculated using only the vertices of the polygon and define the lines between the points as geodesic segments independent of the actual shape of the polygon. A geodesic segment is the shortest path between two points on an ellipsoid. Thus, if you have a line that spans the width of the world, with only two vertices, each on the edges of the map, the geodesic length would be zero (shortest distance between the two vertices).

Namespace:  Esri.ArcGISRuntime.Geometry
Assembly:  Esri.ArcGISRuntime (in Esri.ArcGISRuntime.dll) Version: 100.6.0.0
Syntax
public static double LengthGeodetic(
	Geometry geometry,
	LinearUnit linearUnit = null,
	GeodeticCurveType geodeticCurveType = GeodeticCurveType.Geodesic
)

Parameters

geometry
Type: Esri.ArcGISRuntime.GeometryGeometry
The geometry to calculate the geodesic length for.
linearUnit (Optional)
Type: Esri.ArcGISRuntime.GeometryLinearUnit
The linear unit of measurement the length value will be returned. If null, meters will be used
geodeticCurveType (Optional)
Type: Esri.ArcGISRuntime.GeometryGeodeticCurveType
The type of curve to calculate.

Return Value

Type: Double
The calculated geodesic length in meters.
Examples

WPF

Example Name: GeodesicOperations

This sample demonstrates how to perform geodesic operations on geometries using the GeometryEngine. Geodesic calculations take into account the curvature of the Earth, while planar calculations are based on a 2D Cartesian plane.

Code example screen shot.

C#
// 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 ArcGISRuntime.WPF.Samples.GeodesicOperations
{
    [ArcGISRuntime.Samples.Shared.Attributes.Sample(
        "Geodesic operations",
        "Geometry",
        "This sample demonstrates how to use the Geometry engine to calculate a geodesic path between two points and measure its distance.",
        "Tap on the map to set the end point of a path from New York City. The geodesic path and geodesic distance will be displayed.", "Featured")]
    public partial class GeodesicOperations
    {
        // Hold references to the graphics.
        private Graphic _startLocationGraphic;
        private Graphic _endLocationGraphic;
        private Graphic _pathGraphic;

        public GeodesicOperations()
        {
            InitializeComponent();

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

        private void Initialize()
        {
            MyMapView.Map = new Map(Basemap.CreateImagery());

            // 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.
            MapPoint start = new MapPoint(-73.7781, 40.6413, SpatialReferences.Wgs84);
            SimpleMarkerSymbol startMarker = new SimpleMarkerSymbol(SimpleMarkerSymbolStyle.Circle, System.Drawing.Color.Blue, 10);
            _startLocationGraphic = new Graphic(start, 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)GeometryEngine.Project(geoViewInputEventArgs.Location, 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 = GeometryEngine.DensifyGeodetic(routeLine, 1, LinearUnits.Kilometers, GeodeticCurveType.Geodesic);

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

            // Calculate and show the distance.
            double distance = GeometryEngine.LengthGeodetic(pathGeometry, LinearUnits.Kilometers, GeodeticCurveType.Geodesic);
            ResultsLabel.Text = string.Format("{0} kilometers", (int)distance);
        }
    }
}
XAML
<UserControl x:Class="ArcGISRuntime.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"
                       Text="Tap to set an end point."
                       FontWeight="SemiBold" TextAlignment="Center" />
        </Border>
    </Grid>
</UserControl>
See Also
Additional Examples
Hyperlink to ExampleDescription
GeodesicOperationsThis sample demonstrates how to perform geodesic operations on geometries using the GeometryEngine. Geodesic calculations take into account the curvature of the Earth, while planar calculations are based on a 2D Cartesian plane.