MapMultipointItemMappingBase<T>.YCoordinateMember Property

Specifies the point source data member that contains y-coordinates of points (latitudes for geo points).

Namespace: DevExpress.XtraMap

Assembly: DevExpress.XtraMap.v23.2.dll

NuGet Package: DevExpress.Win.Map

Declaration

C#

[DefaultValue("")]
public string YCoordinateMember { get; set; }

VB.NET

<DefaultValue("")>
Public Property YCoordinateMember As String

Property Value

Type	Default	Description
String	String.Empty	The data member name.

Examples

Create Polylines From a Collection of Points

The following example shows how to create map polylines based on a collection of coordinates, and configure the polyline color and thickness.

Follow the steps below to create a vector layer with polylines:

1. Create a VectorItemsLayer object and add it to the map’s Layers collection.

2. Create a ListSourceDataAdapter object and assign it to the vector layer’s Data property.

3. Specify the adapter’s DataSource. The example below uses a list of objects that store information about lines, such as coordinate points.

4. Set the adapter’s DefaultMapItemType property to MapItemType.Polyline to create polylines based on the data that the adapter loads.

5. Add a MapPolylinePointCollectionMapping object to the adapter’s PropertyMappings. Specify the following mapping properties to define source fields from which the adapter should obtain polyline point data:

   • PointSourceMember – Specifies the data member that stores polylines points.
   • XCoordinateMember – Specifies the point source data member that contains x-coordinates of points (longitudes for geo points).
   • YCoordinateMember – Specifies the point source data member that contains y-coordinates of points (latitudes for geo points).

6. To customize polyline appearance settings, use mappings that correspond to map item properties. For example, add the following mappings to the adapter’s PropertyMappings collection to specify the MapItem.Stroke and MapItem.StrokeWidth properties:

   • MapItemStrokeMapping
   • MapItemStrokeWidthMapping

   You can use a mapping’s DefaultValue property to explicitly specify a map item property value (for example, MapItem.Stroke), or you can use the mapping’s Member property to map the property to a source data member.

7. Call the MapControl.ZoomToFitLayerItems() method in the vector layer’s DataLoaded event handler to specify the map viewport boundaries so that they include all polylines.

The code below creates two polylines:

C#

using DevExpress.XtraMap;
using System.Collections.Generic;
using System.Drawing;
using System.Windows.Forms;

namespace CreateMapLines {
    public partial class Form1 : Form {
        public Form1() {
            InitializeComponent();
            // Create a background image layer and add it to the map.
            ImageLayer imageLayer = new ImageLayer();
            imageLayer.DataProvider = new BingMapDataProvider {
                BingKey = "Insert your Bing Maps key here.",
                Kind = BingMapKind.RoadGray
            };
            mapControl1.Layers.Add(imageLayer);

            // Create a vector layer and add it to the map.
            VectorItemsLayer vectorLayer = new VectorItemsLayer();
            mapControl1.Layers.Add(vectorLayer);

            // Create a ListSourceDataAdapter.
            // Specify its data source.
            // Configure mappings.
            // Assign the adapter to the vector layer.
            ListSourceDataAdapter adapter = new ListSourceDataAdapter();
            adapter.DataSource = GetLines();
            adapter.DefaultMapItemType = MapItemType.Polyline;
            adapter.PropertyMappings.Add(new MapPolylinePointCollectionMapping {
                XCoordinateMember = "Longitude", 
                PointSourceMember = "PointSource", 
                YCoordinateMember= "Latitude"
            });
            adapter.PropertyMappings.Add(new MapItemStrokeMapping { Member = "Color" });
            adapter.PropertyMappings.Add(new MapItemStrokeWidthMapping { DefaultValue = 4 });
            vectorLayer.Data = adapter;
            vectorLayer.DataLoaded += OnVectorLayerDataLoaded;
        }

        private void OnVectorLayerDataLoaded(object sender, DataLoadedEventArgs e) {
            // Zooms the map to fit all created lines.
            mapControl1.ZoomToFitLayerItems();
        }
        public List<Line> GetLines() {
            List<Line> lines = new List<Line>();

            Line line1 = new Line();
            line1.PointSource.Add(new Coordinate(-5.93107, -35.112723));
            line1.PointSource.Add(new Coordinate(-10.13507, -25.15696));
            line1.PointSource.Add(new Coordinate(-5.183714, -8.911391));
            line1.PointSource.Add(new Coordinate(4.253438, 5.47072));
            line1.Color = Color.Green;
            lines.Add(line1);

            Line line2 = new Line();
            line2.PointSource.Add(new Coordinate(1, 0.5));
            line2.PointSource.Add(new Coordinate(-25, -15));
            line2.PointSource.Add(new Coordinate(-15, -25));
            line2.PointSource.Add(new Coordinate(-22.1531, -41.45984));
            line2.Color = Color.Red;
            lines.Add(line2);

            return lines;
        }
    }
    public struct Coordinate {
        public double Latitude { get; }
        public double Longitude { get; }
        public Coordinate(double lat, double lon) {
            Latitude = lat;
            Longitude = lon;
        }
    }
    public class Line {
        public Color Color { get; set; }
        public List<Coordinate> PointSource { get; } = new List<Coordinate>();
    }
}

VB.NET

Imports DevExpress.XtraMap
Imports System.Collections.Generic
Imports System.Drawing
Imports System.Windows.Forms

Namespace CreateMapLines
    Public Partial Class Form1
        Inherits Form

        Public Sub New()
            InitializeComponent()
            ' Create a background image layer and add it to the map.
            Dim imageLayer As ImageLayer = New ImageLayer()
            imageLayer.DataProvider = New BingMapDataProvider With {
                .BingKey = "Insert your Bing Maps key here.",
                .Kind = BingMapKind.RoadGray
            }
            mapControl1.Layers.Add(imageLayer)

            ' Create a vector layer and add it to the map.
            Dim vectorLayer As VectorItemsLayer = New VectorItemsLayer()
            mapControl1.Layers.Add(vectorLayer)

            ' Create a ListSourceDataAdapter.
            ' Specify its data source.
            ' Configure mappings.
            ' Assign the adapter to the vector layer.
            Dim adapter As ListSourceDataAdapter = New ListSourceDataAdapter()
            adapter.DataSource = GetLines()
            adapter.DefaultMapItemType = MapItemType.Polyline
            adapter.PropertyMappings.Add(New MapPolylinePointCollectionMapping With {
                .XCoordinateMember = "Longitude",
                .PointSourceMember = "PointSource",
                .YCoordinateMember = "Latitude"
            })
            adapter.PropertyMappings.Add(New MapItemStrokeMapping With {
                .Member = "Color"
            })
            adapter.PropertyMappings.Add(New MapItemStrokeWidthMapping With {
                .DefaultValue = 4
            })
            vectorLayer.Data = adapter
            vectorLayer.DataLoaded += AddressOf OnVectorLayerDataLoaded
        End Sub

        Private Sub OnVectorLayerDataLoaded(ByVal sender As Object, ByVal e As DataLoadedEventArgs)
            ' Zooms the map so that it displays all created lines.
            mapControl1.ZoomToFitLayerItems()
        End Sub

        Public Function GetLines() As List(Of Line)
            Dim lines As List(Of Line) = New List(Of Line)()
            Dim line1 As Line = New Line()
            line1.PointSource.Add(New Coordinate(-5.93107, -35.112723))
            line1.PointSource.Add(New Coordinate(-10.13507, -25.15696))
            line1.PointSource.Add(New Coordinate(-5.183714, -8.911391))
            line1.PointSource.Add(New Coordinate(4.253438, 5.47072))
            line1.Color = Color.Green
            lines.Add(line1)
            Dim line2 As Line = New Line()
            line2.PointSource.Add(New Coordinate(1, 0.5))
            line2.PointSource.Add(New Coordinate(-25, -15))
            line2.PointSource.Add(New Coordinate(-15, -25))
            line2.PointSource.Add(New Coordinate(-22.1531, -41.45984))
            line2.Color = Color.Red
            lines.Add(line2)
            Return lines
        End Function
    End Class

    Public Structure Coordinate
        Public ReadOnly Property Latitude As Double
        Public ReadOnly Property Longitude As Double

        Public Sub New(ByVal lat As Double, ByVal lon As Double)
            Latitude = lat
            Longitude = lon
        End Sub
    End Structure

    Public Class Line
        Public Property Color As Color
        Public ReadOnly Property PointSource As List(Of Coordinate) = New List(Of Coordinate)()
    End Class
End Namespace

Create Polygons From a Collection of Points

The following example shows how to create map polygons based on a collection of coordinates, and configure the polygon stroke and fill colors.

Follow the steps below to create a vector layer with polygons:

1. Create a VectorItemsLayer object and add it to the map’s Layers collection.

2. Create a ListSourceDataAdapter object and assign it to the vector layer’s Data property.

3. Specify the adapter’s DataSource. The example below uses a list of objects that store information about polygons, such as coordinate points.

4. Set the adapter’s DefaultMapItemType property to MapItemType.Polygon to create polygon based on the data that the adapter loads.

5. Add a MapPolygonPointCollectionMapping object to the adapter’s PropertyMappings. Specify the following mapping properties to define source fields from which the adapter should obtain polygon point data:

   • PointSourceMember – Specifies the data member that stores polygon points.
   • XCoordinateMember – Specifies the point source data member that contains x-coordinates of points (longitudes for geo points).
   • YCoordinateMember – Specifies the point source data member that contains y-coordinates of points (latitudes for geo points).

6. To customize polygon appearance settings, use mappings that correspond to map item properties. For example, add the following mappings to the adapter’s PropertyMappings collection to specify the MapItem.Stroke, MapItem.Fill, and MapItem.StrokeWidth properties:

   • MapItemStrokeMapping
   • MapItemFillMapping
   • MapItemStrokeWidthMapping

   You can use a mapping’s DefaultValue property to explicitly specify a map item property value (for example, MapItem.Stroke), or you can use the mapping’s Member property to map the property to a source data member.

7. Call the MapControl.ZoomToFitLayerItems() method in the vector layer’s DataLoaded event handler to specify the map viewport boundaries so that they include all polygons.

The code below creates two polygons:

C#

using DevExpress.XtraMap;
using System.Collections.Generic;
using System.Drawing;
using System.Windows.Forms;

namespace CreateMapPolygons {
    public partial class Form1 : Form {
        public Form1() {
            InitializeComponent();
            // Create a background image layer and add it to the map.
            ImageLayer imageLayer = new ImageLayer();
            imageLayer.DataProvider = new BingMapDataProvider {
                BingKey = "Insert your Bing Maps key here.",
                Kind = BingMapKind.RoadGray
            };
            mapControl1.Layers.Add(imageLayer);

            // Create a vector layer and add it to the map.
            VectorItemsLayer vectorLayer = new VectorItemsLayer();
            mapControl1.Layers.Add(vectorLayer);

            // Create a ListSourceDataAdapter.
            // Specify its data source.
            // Configure mappings.
            // Assign the adapter to the vector layer.
            ListSourceDataAdapter adapter = new ListSourceDataAdapter();
            adapter.DataSource = GetPolygons();
            adapter.DefaultMapItemType = MapItemType.Polygon;
            adapter.PropertyMappings.Add(new MapPolygonPointCollectionMapping {
                XCoordinateMember = "Longitude",
                PointSourceMember = "PointSource",
                YCoordinateMember = "Latitude"
            });
            adapter.PropertyMappings.Add(new MapItemStrokeMapping { Member = "StrokeColor" });
            adapter.PropertyMappings.Add(new MapItemFillMapping { Member = "FillColor" });
            adapter.PropertyMappings.Add(new MapItemStrokeWidthMapping { DefaultValue = 4 });
            vectorLayer.Data = adapter;
            vectorLayer.DataLoaded += OnVectorLayerDataLoaded;
        }

        private void OnVectorLayerDataLoaded(object sender, DataLoadedEventArgs e) {
            // Zooms the map so that it displays all created polygons.
            mapControl1.ZoomToFitLayerItems(paddingFactor: 0.5);
        }
        public List<Polygon> GetPolygons() {
            List<Polygon> polygons = new List<Polygon>();

            Polygon polygon1 = new Polygon();
            polygon1.PointSource.Add(new Coordinate(-3.5, -30.3));
            polygon1.PointSource.Add(new Coordinate(-2.4, -9.8));
            polygon1.PointSource.Add(new Coordinate(-9.0, -19.4));
            polygon1.PointSource.Add(new Coordinate(-12.9, -31.1));
            polygon1.StrokeColor = Color.Green;
            polygon1.FillColor = Color.White;
            polygons.Add(polygon1);

            Polygon polygon2 = new Polygon();
            polygon2.PointSource.Add(new Coordinate(-13.5, -9.6));
            polygon2.PointSource.Add(new Coordinate(-17.5, 0.3));
            polygon2.PointSource.Add(new Coordinate(-21.8, -7.8));
            polygon2.StrokeColor = Color.Red;
            polygon2.FillColor = Color.DarkGray;
            polygons.Add(polygon2);

            return polygons;
        }
    }
    public struct Coordinate {
        public double Latitude { get; }
        public double Longitude { get; }
        public Coordinate(double lat, double lon) {
            Latitude = lat;
            Longitude = lon;
        }
    }
    public class Polygon {
        public Color StrokeColor { get; set; }
        public Color FillColor { get; set; }
        public List<Coordinate> PointSource { get; } = new List<Coordinate>();
    }
}

VB.NET

Imports DevExpress.XtraMap
Imports System.Collections.Generic
Imports System.Drawing
Imports System.Windows.Forms

Namespace CreateMapPolygons
    Public Partial Class Form1
        Inherits Form

        Public Sub New()
            InitializeComponent()
            ' Create a background image layer and add it to the map.
            Dim imageLayer As ImageLayer = New ImageLayer()
            imageLayer.DataProvider = New BingMapDataProvider With {
                .BingKey = "Insert your Bing Maps key here.",
                .Kind = BingMapKind.RoadGray
            }
            mapControl1.Layers.Add(imageLayer)

            ' Create a vector layer and add it to the map.
            Dim vectorLayer As VectorItemsLayer = New VectorItemsLayer()
            mapControl1.Layers.Add(vectorLayer)

            ' Create a ListSourceDataAdapter.
            ' Specify its data source.
            ' Configure mappings.
            ' Assign the adapter to the vector layer.
            Dim adapter As ListSourceDataAdapter = New ListSourceDataAdapter()
            adapter.DataSource = GetPolygons()
            adapter.DefaultMapItemType = MapItemType.Polygon
            adapter.PropertyMappings.Add(New MapPolygonPointCollectionMapping With {
                .XCoordinateMember = "Longitude",
                .PointSourceMember = "PointSource",
                .YCoordinateMember = "Latitude"
            })
            adapter.PropertyMappings.Add(New MapItemStrokeMapping With {
                .Member = "StrokeColor"
            })
            adapter.PropertyMappings.Add(New MapItemFillMapping With {
                .Member = "FillColor"
            })
            adapter.PropertyMappings.Add(New MapItemStrokeWidthMapping With {
                .DefaultValue = 4
            })
            vectorLayer.Data = adapter
            vectorLayer.DataLoaded += AddressOf OnVectorLayerDataLoaded
        End Sub

        Private Sub OnVectorLayerDataLoaded(ByVal sender As Object, ByVal e As DataLoadedEventArgs)
            ' Zooms the map so that it displays all created polygons.
            mapControl1.ZoomToFitLayerItems(paddingFactor:=0.5)
        End Sub

        Public Function GetPolygons() As List(Of Polygon)
            Dim polygons As List(Of Polygon) = New List(Of Polygon)()
            Dim polygon1 As Polygon = New Polygon()
            polygon1.PointSource.Add(New Coordinate(-3.5, -30.3))
            polygon1.PointSource.Add(New Coordinate(-2.4, -9.8))
            polygon1.PointSource.Add(New Coordinate(-9.0, -19.4))
            polygon1.PointSource.Add(New Coordinate(-12.9, -31.1))
            polygon1.StrokeColor = Color.Green
            polygon1.FillColor = Color.White
            polygons.Add(polygon1)
            Dim polygon2 As Polygon = New Polygon()
            polygon2.PointSource.Add(New Coordinate(-13.5, -9.6))
            polygon2.PointSource.Add(New Coordinate(-17.5, 0.3))
            polygon2.PointSource.Add(New Coordinate(-21.8, -7.8))
            polygon2.StrokeColor = Color.Red
            polygon2.FillColor = Color.DarkGray
            polygons.Add(polygon2)
            Return polygons
        End Function
    End Class

    Public Structure Coordinate
        Public ReadOnly Property Latitude As Double
        Public ReadOnly Property Longitude As Double

        Public Sub New(ByVal lat As Double, ByVal lon As Double)
            Latitude = lat
            Longitude = lon
        End Sub
    End Structure

    Public Class Polygon
        Public Property StrokeColor As Color
        Public Property FillColor As Color
        Public ReadOnly Property PointSource As List(Of Coordinate) = New List(Of Coordinate)()
    End Class
End Namespace