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GeometryEngineNearestVertex Method

Returns a ProximityResult that describes the nearest vertex in the input geometry to the input point.

Namespace:  Esri.ArcGISRuntime.Geometry
Assembly:  Esri.ArcGISRuntime (in Esri.ArcGISRuntime.dll) Version: 100.9.0
Syntax
public static ProximityResult NearestVertex(
	Geometry geometry,
	MapPoint point
)

Parameters

geometry
Type: Esri.ArcGISRuntime.GeometryGeometry
The geometry in which the nearest vertex to a specified point is to be found.
point
Type: Esri.ArcGISRuntime.GeometryMapPoint
The point which to find the nearest vertex to.

Return Value

Type: ProximityResult
The proximity result.
Remarks

Input geometry of type Envelope is not supported. To find the nearest vertex on an Envelope, convert it to a Polygon first.

If the specified geometry is a polyline or polygon the nearest vertex is the closest ending position of the line segment that comprises geometry; it may not necessarily be the closest point of the line segment. If you want to obtain the closest point in the polyline or polygon use the NearestCoordinate(Geometry, MapPoint) Method instead.

Examples

WPF

Example Name: NearestVertex

Find the closest vertex and coordinate of a geometry to a point.

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

namespace ArcGISRuntime.WPF.Samples.NearestVertex
{
    [ArcGISRuntime.Samples.Shared.Attributes.Sample(
        name: "Nearest vertex",
        category: "Geometry",
        description: "Find the closest vertex and coordinate of a geometry to a point.",
        instructions: "Click anywhere on the map. An orange cross will show at that location. A blue circle will show the polygon's nearest vertex to the point that was clicked. A red diamond will appear at the coordinate on the geometry that is nearest to the point that was clicked. If clicked inside the geometry, the red and orange markers will overlap. The information box showing distance between the clicked point and the nearest vertex/coordinate will be updated with every new location clicked.",
        tags: new[] { "analysis", "coordinate", "geometry", "nearest", "proximity", "vertex" })]
    public partial class NearestVertex
    {
        // Hold references to the graphics overlay and the polygon graphic
        private GraphicsOverlay _graphicsOverlay;
        private Graphic _polygonGraphic;

        // Hold references to the graphics for the user and results points
        private Graphic _tappedLocationGraphic;
        private Graphic _nearestVertexGraphic;
        private Graphic _nearestCoordinateGraphic;

        public NearestVertex()
        {
            InitializeComponent();

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

        private void Initialize()
        {
            // Configure the basemap
            MyMapView.Map = new Map(Basemap.CreateTopographic());

            // Create the graphics overlay and set the selection color
            _graphicsOverlay = new GraphicsOverlay();

            // Add the overlay to the MapView
            MyMapView.GraphicsOverlays.Add(_graphicsOverlay);

            // Create the point collection that defines the polygon
            PointCollection polygonPoints = new PointCollection(SpatialReferences.WebMercator)
            {
                new MapPoint(-5991501.677830, 5599295.131468),
                new MapPoint(-6928550.398185, 2087936.739807),
                new MapPoint(-3149463.800709, 1840803.011362),
                new MapPoint(-1563689.043184, 3714900.452072),
                new MapPoint(-3180355.516764, 5619889.608838)
            };

            // Create the polygon
            Polygon polygonGeometry = new Polygon(polygonPoints);

            // Define and apply the symbology
            SimpleLineSymbol polygonOutlineSymbol = new SimpleLineSymbol(SimpleLineSymbolStyle.Solid, System.Drawing.Color.Green, 2);
            SimpleFillSymbol polygonFillSymbol = new SimpleFillSymbol(SimpleFillSymbolStyle.ForwardDiagonal, System.Drawing.Color.Green, polygonOutlineSymbol);

            // Create the graphic and add it to the graphics overlay
            _polygonGraphic = new Graphic(polygonGeometry, polygonFillSymbol);
            _graphicsOverlay.Graphics.Add(_polygonGraphic);

            // Create the graphics and symbology for the tapped point, the nearest vertex, and the nearest coordinate
            SimpleMarkerSymbol tappedLocationSymbol = new SimpleMarkerSymbol(SimpleMarkerSymbolStyle.X, System.Drawing.Color.Orange, 15);
            SimpleMarkerSymbol nearestCoordinateSymbol = new SimpleMarkerSymbol(SimpleMarkerSymbolStyle.Diamond, System.Drawing.Color.Red, 10);
            SimpleMarkerSymbol nearestVertexSymbol = new SimpleMarkerSymbol(SimpleMarkerSymbolStyle.Circle, System.Drawing.Color.Blue, 15);
            _nearestCoordinateGraphic = new Graphic { Symbol = nearestCoordinateSymbol };
            _tappedLocationGraphic = new Graphic { Symbol = tappedLocationSymbol };
            _nearestVertexGraphic = new Graphic { Symbol = nearestVertexSymbol };

            _graphicsOverlay.Graphics.Add(_tappedLocationGraphic);
            _graphicsOverlay.Graphics.Add(_nearestVertexGraphic);
            _graphicsOverlay.Graphics.Add(_nearestCoordinateGraphic);

            // Listen for taps; the spatial relationships will be updated in the handler
            MyMapView.GeoViewTapped += MapViewTapped;

            // Center the map on the polygon
            MyMapView.SetViewpointCenterAsync(polygonGeometry.Extent.GetCenter(), 200000000);
        }

        private void MapViewTapped(object sender, GeoViewInputEventArgs geoViewInputEventArgs)
        {
            // Get the tapped location
            MapPoint tappedLocation = (MapPoint)GeometryEngine.NormalizeCentralMeridian(geoViewInputEventArgs.Location);

            // Show the tapped location
            _tappedLocationGraphic.Geometry = tappedLocation;

            // Get the nearest vertex in the polygon
            ProximityResult nearestVertexResult = GeometryEngine.NearestVertex(_polygonGraphic.Geometry, tappedLocation);

            // Get the nearest coordinate in the polygon
            ProximityResult nearestCoordinateResult =
                GeometryEngine.NearestCoordinate(_polygonGraphic.Geometry, tappedLocation);

            // Get the distance to the nearest vertex in the polygon
            int distanceVertex = (int)(nearestVertexResult.Distance / 1000);

            // Get the distance to the nearest coordinate in the polygon
            int distanceCoordinate = (int)(nearestCoordinateResult.Distance / 1000);

            // Show the nearest vertex in blue
            _nearestVertexGraphic.Geometry = nearestVertexResult.Coordinate;

            // Show the nearest coordinate in red
            _nearestCoordinateGraphic.Geometry = nearestCoordinateResult.Coordinate;

            // Show the distances in the UI
            ResultsLabel.Content =
                string.Format("Vertex dist: {0} km, Point dist: {1} km", distanceVertex, distanceCoordinate);
        }
    }
}
XAML
<UserControl
    x:Class="ArcGISRuntime.WPF.Samples.NearestVertex.NearestVertex"
    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}">
            <StackPanel>
                <Label
                    x:Name="ResultsLabel"
                    HorizontalContentAlignment="Center"
                    Content="Tap to see the nearest vertex and point."
                    FontWeight="SemiBold" />
            </StackPanel>
        </Border>
    </Grid>
</UserControl>
See Also
Additional Examples
Hyperlink to ExampleDescription
NearestVertexFind the closest vertex and coordinate of a geometry to a point.