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ReadOnlyPart Class

Represents an single part of an multipart geometry (polygon or polyline).
Inheritance Hierarchy
SystemObject
  Esri.ArcGISRuntime.GeometryReadOnlyPart

Namespace:  Esri.ArcGISRuntime.Geometry
Assembly:  Esri.ArcGISRuntime (in Esri.ArcGISRuntime.dll) Version: 100.9.0
Syntax
public class ReadOnlyPart : IReadOnlyList<Segment>, 
	IReadOnlyCollection<Segment>, IEnumerable<Segment>, IEnumerable

The ReadOnlyPart type exposes the following members.

Properties
  NameDescription
Public propertyCount
Public propertyEndPoint
Returns the end point of the last segment in the part. Returns NULL if the collection is empty.
Public propertyHasCurves
Gets a flag indicating whether the part has any curves.
Public propertyIsEmpty
Indicates if the part contains no segments.
Public propertyItem
Gets or sets the element at the specified index.
Public propertyPointCount
Returns the count of points in the part.
Public propertyCode examplePoints
Returns all the points that are vertexes of the part.
Public propertySegmentCount
Returns the count of segments in the part.
Public propertySpatialReference
Retrieve the spatial reference for the immutable part.
Public propertyStartPoint
Returns the start point of the first segment in the part. Returns NULL if the collection is empty.
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Methods
  NameDescription
Public methodGetEndPointIndexFromSegmentIndex
For a segment at a specified segment_index the method returns the point index of the segment's end point.
Public methodGetEnumerator
Returns an enumerator that iterates through the collection.
Public methodGetSegmentIndexFromEndPointIndex
Converts from a point index to a segment index that uses the given point as an end point. If the point is not an end point then a value equivalent to -1 value is returned.
Public methodGetSegmentIndexFromPointIndex
Converts from a point index to a segment index of the start point and another segment index containing the end point. If the point is not a start or end point a value equivalent to -1 is set.
Public methodGetSegmentIndexFromStartPointIndex
Converts from a point index to a segment index that uses the given point as a start point. If the point is not a start point then a value equivalent to -1 value is returned.
Public methodGetStartPointIndexFromSegmentIndex
For a segment at a specified segment_index the method returns the point index of the segment's start point.
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Remarks
This class is used to represent a part in a multipart geometry. This is a collection of segments. The points that are the vertices of the segments are also accessible.
Examples

WPF

Example Name: DensifyAndGeneralize

A multipart geometry can be densified by adding interpolated points at regular intervals. Generalizing multipart geometry simplifies it while preserving its general shape. Densifying a multipart geometry adds more vertices at regular intervals.

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 System.Drawing;
using System.Linq;

namespace ArcGISRuntime.WPF.Samples.DensifyAndGeneralize
{
    [ArcGISRuntime.Samples.Shared.Attributes.Sample(
        name: "Densify and generalize",
        category: "Geometry",
        description: "A multipart geometry can be densified by adding interpolated points at regular intervals. Generalizing multipart geometry simplifies it while preserving its general shape. Densifying a multipart geometry adds more vertices at regular intervals.",
        instructions: "Use the sliders to control the parameters of the densify and generalize methods.",
        tags: new[] { "data", "densify", "generalize", "simplify" })]
    public partial class DensifyAndGeneralize
    {
        // Graphic used to refer to the original geometry.
        private Polyline _originalPolyline;

        // Graphics used to show the densify or generalize result.
        private Graphic _resultPolylineGraphic;
        private Graphic _resultPointGraphic;

        public DensifyAndGeneralize()
        {
            InitializeComponent();

            // Create the map with a default basemap.
            MyMapView.Map = new Map(Basemap.CreateStreetsNightVector());

            // Create and add a graphics overlay.
            GraphicsOverlay overlay = new GraphicsOverlay();
            MyMapView.GraphicsOverlays.Add(overlay);

            // Create the original geometry: some points along a river.
            PointCollection points = CreateShipPoints();

            // Show the original geometry as red dots on the map.
            Multipoint originalMultipoint = new Multipoint(points);
            Graphic originalPointsGraphic = new Graphic(originalMultipoint,
                new SimpleMarkerSymbol(SimpleMarkerSymbolStyle.Circle, Color.Red, 7));
            overlay.Graphics.Add(originalPointsGraphic);

            // Show a dotted red line connecting the original points.
            _originalPolyline = new Polyline(points);
            Graphic originalPolylineGraphic = new Graphic(_originalPolyline,
                new SimpleLineSymbol(SimpleLineSymbolStyle.Dot, Color.Red, 3));
            overlay.Graphics.Add(originalPolylineGraphic);

            // Show the result (densified or generalized) points as magenta dots on the map.
            _resultPointGraphic = new Graphic
            {
                Symbol = new SimpleMarkerSymbol(SimpleMarkerSymbolStyle.Circle, Color.Magenta, 7)
            };
            overlay.Graphics.Add(_resultPointGraphic);

            // Connect the result points with a magenta polyline.
            _resultPolylineGraphic = new Graphic
            {
                Symbol = new SimpleLineSymbol(SimpleLineSymbolStyle.Solid, Color.Magenta, 3)
            };
            overlay.Graphics.Add(_resultPolylineGraphic);

            // Listen for changes in state.
            DeviationSlider.ValueChanged += (o, e) =>
                UpdateGeometry("Generalize", SegmentLengthSlider.Value, DeviationSlider.Value);
            SegmentLengthSlider.ValueChanged += (o, e) =>
                UpdateGeometry("Densify", SegmentLengthSlider.Value, DeviationSlider.Value);

            // Center the map.
            MyMapView.SetViewpointGeometryAsync(_originalPolyline.Extent, 100);
        }

        private void UpdateGeometry(string operation, double segmentLength, double deviation)
        {
            // Start with the original polyline.
            Polyline polyline = _originalPolyline;

            // Apply the selected operation.
            if (operation == "Generalize")
            {
                // Reset the other slider.
                SegmentLengthSlider.Value = 100;

                polyline = (Polyline) GeometryEngine.Generalize(polyline, deviation, true);

                // Update the result label.
                ResultLabel.Text = string.Format("Operation: Generalize, Deviation: {0:f}", deviation);
            }
            else
            {
                // Reset the other slider.
                DeviationSlider.Value = 10;

                polyline = (Polyline) GeometryEngine.Densify(polyline, segmentLength);

                // Update the result label.
                ResultLabel.Text = string.Format("Operation: Densify, Segment length: {0:f}", segmentLength);
            }

            // Update the graphic geometries to show the results.
            _resultPolylineGraphic.Geometry = polyline;
            _resultPointGraphic.Geometry = new Multipoint(polyline.Parts.SelectMany(m => m.Points));
        }

        private static PointCollection CreateShipPoints()
        {
            return new PointCollection(SpatialReference.Create(32126))
            {
                new MapPoint(2330611.130549, 202360.002957, 0.000000),
                new MapPoint(2330583.834672, 202525.984012, 0.000000),
                new MapPoint(2330574.164902, 202691.488009, 0.000000),
                new MapPoint(2330689.292623, 203170.045888, 0.000000),
                new MapPoint(2330696.773344, 203317.495798, 0.000000),
                new MapPoint(2330691.419723, 203380.917080, 0.000000),
                new MapPoint(2330435.065296, 203816.662457, 0.000000),
                new MapPoint(2330369.500800, 204329.861789, 0.000000),
                new MapPoint(2330400.929891, 204712.129673, 0.000000),
                new MapPoint(2330484.300447, 204927.797132, 0.000000),
                new MapPoint(2330514.469919, 205000.792463, 0.000000),
                new MapPoint(2330638.099138, 205271.601116, 0.000000),
                new MapPoint(2330725.315888, 205631.231308, 0.000000),
                new MapPoint(2330755.640702, 206433.354860, 0.000000),
                new MapPoint(2330680.644719, 206660.240923, 0.000000),
                new MapPoint(2330386.957926, 207340.947204, 0.000000),
                new MapPoint(2330485.861737, 207742.298501, 0.000000)
            };
        }
    }
}
XAML
<UserControl x:Class="ArcGISRuntime.WPF.Samples.DensifyAndGeneralize.DensifyAndGeneralize"
             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}">
            <Grid>
                <Grid.RowDefinitions>
                    <RowDefinition Height="Auto" />
                    <RowDefinition Height="Auto" />
                    <RowDefinition Height="Auto" />
                    <RowDefinition Height="Auto" />
                    <RowDefinition Height="Auto" />
                    <RowDefinition Height="Auto" />
                </Grid.RowDefinitions>
                <TextBlock Text="Adjust the sliders to see the resulting generalized or densified polyline."
                           Grid.Row="0" Margin="0,0,0,15"
                           TextWrapping="Wrap" FontWeight="Bold" />
                <TextBlock Text="Max. Deviation (Generalize)"
                           Grid.Row="1"
                           FontWeight="SemiBold" />
                <Slider x:Name="DeviationSlider"
                        Grid.Row="2" Margin="0,5,0,0"
                        Value="10" Minimum="1" Maximum="250" />
                <TextBlock Text="Max. Segment length (Densify)"
                           Grid.Row="3"
                           FontWeight="SemiBold" />
                <Slider x:Name="SegmentLengthSlider"
                        Grid.Row="4" Margin="0,5,0,5"
                        Value="100" Minimum="100" Maximum="500" />
                <TextBlock x:Name="ResultLabel"
                           Grid.Row="5"
                           Text="Adjust a slider to start"
                           TextWrapping="Wrap" FontWeight="SemiBold" Foreground="Blue" />
            </Grid>
        </Border>
    </Grid>
</UserControl>
See Also
Additional Examples
Hyperlink to ExampleDescription
DensifyAndGeneralizeA multipart geometry can be densified by adding interpolated points at regular intervals. Generalizing multipart geometry simplifies it while preserving its general shape. Densifying a multipart geometry adds more vertices at regular intervals.