How to: Specify a Map Projection

• Nov 13, 2018
• 2 minutes to read

This example demonstrates how to specify the map projection that is used to display geographical data for a Map Control.

To configure a map projection, specify the GeoMapCoordinateSystem.Projection property of the GeoMapCoordinateSystem object. Assign it to the MapControl.CoordinateSystem property.

One of the following predefined map projections can be used.

• BraunStereographicProjection;
• EllipticalMercatorProjection;
• EqualAreaProjection;
• EquidistantProjection;
• EquirectangularProjection;
• KavrayskiyProjection;
• LambertCylindricalEqualAreaProjection;
• MillerProjection;
• SinusoidalProjection;
• SphericalMercatorProjection;
• Etrs89LambertAzimuthalEqualAreaProjection.

Form1.cs

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

namespace MapProjections {
    public partial class Form1 : Form {
        const string filepath = @"..\..\Data\Countries.shp";
        List<ProjectionBase> mapProjections = new List<ProjectionBase>() {
            new BraunStereographicProjection(),
            new EllipticalMercatorProjection(),
            new EqualAreaProjection(),
            new EquidistantProjection(),
            new EquirectangularProjection(),
            new KavrayskiyProjection(),
            new LambertCylindricalEqualAreaProjection(),
            new MillerProjection(),
            new SinusoidalProjection(),
            new SphericalMercatorProjection(),
            new Etrs89LambertAzimuthalEqualAreaProjection()
        };

        GeoMapCoordinateSystem CoordinateSystem { get { return mapControl.CoordinateSystem as GeoMapCoordinateSystem; } }

        public Form1() {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e) {
            lbProjection.DataSource = mapProjections;
            lbProjection.SetSelected(0, true);

            Uri baseUri = new Uri(System.Reflection.Assembly.GetEntryAssembly().Location);         
            Uri uri = new Uri(baseUri, filepath);
            mapControl.Layers.Add(new VectorItemsLayer() {
                Data = new ShapefileDataAdapter() {
                    FileUri = uri
                }
            });
        }

        private void lbProjection_SelectedIndexChanged(object sender, EventArgs e) {
            CoordinateSystem.Projection = lbProjection.SelectedValue as ProjectionBase;
        }
    }
}

Form1.vb

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

Namespace MapProjections
    Partial Public Class Form1
        Inherits Form

        Private Const filepath As String = "..\..\Data\Countries.shp"
        Private mapProjections As New List(Of ProjectionBase)() From {
            New BraunStereographicProjection(),
            New EllipticalMercatorProjection(),
            New EqualAreaProjection(),
            New EquidistantProjection(),
            New EquirectangularProjection(),
            New KavrayskiyProjection(),
            New LambertCylindricalEqualAreaProjection(),
            New MillerProjection(),
            New SinusoidalProjection(),
            New SphericalMercatorProjection(),
            New Etrs89LambertAzimuthalEqualAreaProjection()
        }

        Private ReadOnly Property CoordinateSystem() As GeoMapCoordinateSystem
            Get
                Return TryCast(mapControl.CoordinateSystem, GeoMapCoordinateSystem)
            End Get
        End Property

        Public Sub New()
            InitializeComponent()
        End Sub

        Private Sub Form1_Load(ByVal sender As Object, ByVal e As EventArgs) Handles MyBase.Load
            lbProjection.DataSource = mapProjections
            lbProjection.SetSelected(0, True)

            Dim baseUri As New Uri(System.Reflection.Assembly.GetEntryAssembly().Location)
            Dim uri As New Uri(baseUri, filepath)
            mapControl.Layers.Add(New VectorItemsLayer() With { _
                .Data = New ShapefileDataAdapter() With {.FileUri = uri} _
            })
        End Sub

        Private Sub lbProjection_SelectedIndexChanged(ByVal sender As Object, ByVal e As EventArgs) Handles lbProjection.SelectedIndexChanged
            CoordinateSystem.Projection = TryCast(lbProjection.SelectedValue, ProjectionBase)
        End Sub
    End Class
End Namespace