using System;  
 using System.Collections.Generic;  
 using System.Linq;  
 using System.Text;  
 using ThinkGeo.MapSuite.Core;  
 
 namespace PolygonAcross180Meridian  
 {  
     //This class, inheriting from Projection, applies the very simple projection of offsetting all the points  
     //360 degrees to the left.  
 
     class OffsetProjection: Projection, IDisposable  
     {  
         protected override Vertex[] ConvertToExternalProjectionCore(double[] x, double[] y)  
         {  
 
             Vertex[] vertices = new Vertex[x.Length];  
 
             for (int i = 0; i < vertices.Length; i++)  
             {  
                 vertices[i] = new Vertex(x[i] - 360, y[i]);  
             }  
             return vertices;  
         }  
 
         protected override Vertex[] ConvertToInternalProjectionCore(double[] x, double[] y)  
         {  
             Vertex[] vertices = new Vertex[x.Length];  
 
             for (int i = 0; i < vertices.Length; i++)  
             {  
                 vertices[i] = new Vertex(x[i] + 360, y[i]);  
             }  
             return vertices;  
         }  
 
         public void Dispose()  
         {  
             Dispose(true);  
             GC.SuppressFinalize(this);  
         }  
 
         private void Dispose(bool disposing)  
         {  
             Close();  
         }  
 
     }  
 }  
 

 using System;  
 using System.Collections.Generic;  
 using System.Linq;  
 using System.Windows.Forms;  
 
 namespace PolygonAcross180Meridian  
 {  
     static class Program  
     {  
         /// <summary>  
         /// The main entry point for the application.  
         /// </summary>  
         [STAThread]  
         static void Main()  
         {  
             Application.EnableVisualStyles();  
             Application.SetCompatibleTextRenderingDefault(false);  
             Application.Run(new TestForm());  
         }  
     }  
 }  
 

 using System;  
 using System.Collections.ObjectModel;  
 using System.Drawing;  
 using System.Windows.Forms;  
 using ThinkGeo.MapSuite.Core;  
 
 namespace PolygonAcross180Meridian  
 {  
     public partial class TestForm : Form  
     {  
         private MapEngine mapEngine = new MapEngine();  
         private Bitmap bitmap = null;  
 
        public TestForm()  
         {  
             InitializeComponent();  
         }  
 
         private void TestForm_Load(object sender, EventArgs e)  
         {  
             // Set the extent and the background color  
             mapEngine.CurrentExtent = ExtentHelper.GetDrawingExtent(new RectangleShape(-198,115,198,-115), Map.Width, Map.Height);  
             mapEngine.BackgroundFillBrush = new GeoSolidBrush(GeoColor.GeographicColors.ShallowOcean);  
 
             //Displays the World Map Kit as a background.  
             ThinkGeo.MapSuite.Core.WorldMapKitLayer worldMapKitLayer = new ThinkGeo.MapSuite.Core.WorldMapKitLayer();  
 
             InMemoryFeatureLayer inMemoryFeatureLayer = new InMemoryFeatureLayer();  
             inMemoryFeatureLayer.ZoomLevelSet.ZoomLevel01.DefaultAreaStyle = AreaStyles.CreateSimpleAreaStyle(GeoColor.FromArgb(150, GeoColor.StandardColors.Red),  
                                                                              GeoColor.StandardColors.Black);  
             inMemoryFeatureLayer.ZoomLevelSet.ZoomLevel01.ApplyUntilZoomLevel = ApplyUntilZoomLevel.Level20;  
 
             inMemoryFeatureLayer.Open();  
             inMemoryFeatureLayer.EditTools.BeginTransaction();  
 
             OffsetProjection offsetProjection = new OffsetProjection();  
             offsetProjection.Open();  
 
             //Original PolygonShape with the unchanged Longitude and Latitude values.  
             PolygonShape polygonShape = new PolygonShape();  
             RingShape ringShape = new RingShape();  
             ringShape.Vertices.Add(new Vertex(-176.21, 43.51));  
             ringShape.Vertices.Add(new Vertex(-157.83, 20.81));  
             ringShape.Vertices.Add(new Vertex(-174.05, 4.59));  
             ringShape.Vertices.Add(new Vertex(171.35, 20.81));  
             ringShape.Vertices.Add(new Vertex(161.62, 12.16));  
             ringShape.Vertices.Add(new Vertex(156.21, 37.02));  
             ringShape.Vertices.Add(new Vertex(168.10, 53.24));  
             ringShape.Vertices.Add(new Vertex(-176.21, 43.51));  
             polygonShape.OuterRing = ringShape;  
 
             inMemoryFeatureLayer.EditTools.Add(new Feature(SplitPolygonAt180Meridian(polygonShape)));  
 
             inMemoryFeatureLayer.EditTools.CommitTransaction();  
             inMemoryFeatureLayer.Close();  
 
             mapEngine.StaticLayers.Add(worldMapKitLayer);  
             mapEngine.DynamicLayers.Add(inMemoryFeatureLayer);  
 
             DrawImage();  
         }  
 
         private MultipolygonShape SplitPolygonAt180Meridian(PolygonShape polygonShape)  
         {  
             //This function gets the MultipolygonShape so that the shape is displayed correctly on decimal degrees map  
             //split at the 180 degree of longitude.  
             OffsetProjection offsetProjection = new OffsetProjection();  
             offsetProjection.Open();  
 
             //RectangleShape of the world used for the Intersection geometric function.  
             RectangleShape worldExtent = new RectangleShape(-180, 90, 180, -90);  
 
             RingShape westernRingShape = new RingShape();  
             RingShape easternRingShape = new RingShape();  
 
             foreach (Vertex vertex in polygonShape.OuterRing.Vertices)  
             {  
                 if (vertex.X > 0)  
                 {  
                     westernRingShape.Vertices.Add(offsetProjection.ConvertToExternalProjection(vertex.X, vertex.Y));  
                     easternRingShape.Vertices.Add(vertex);  
                 }  
                 else  
                 {  
                     westernRingShape.Vertices.Add(vertex);  
                     easternRingShape.Vertices.Add(offsetProjection.ConvertToInternalProjection(vertex.X, vertex.Y));  
                 }  
             }  
             offsetProjection.Close();  
 
             MultipolygonShape multiPolygonShape = new MultipolygonShape();  
             PolygonShape westernPolygonShape = new PolygonShape();  
             PolygonShape easternPolygonShape = new PolygonShape();  
             westernPolygonShape.OuterRing = westernRingShape;  
             easternPolygonShape.OuterRing = easternRingShape;  
 
            MultipolygonShape westernMultiPolygonShape = worldExtent.GetIntersection(westernPolygonShape);  
            MultipolygonShape easternMultiPolygonShape = worldExtent.GetIntersection(easternPolygonShape);  
 
            foreach (PolygonShape polygonShape1 in westernMultiPolygonShape.Polygons)  
            {  
                multiPolygonShape.Polygons.Add(polygonShape1);  
            }  
            foreach (PolygonShape polygonShape1 in easternMultiPolygonShape.Polygons)  
            {  
                multiPolygonShape.Polygons.Add(polygonShape1);  
            }  
 
             return multiPolygonShape;  
         }  
 
         private void DrawImage()  
         {  
             if (bitmap != null) { bitmap.Dispose(); }  
             bitmap = new Bitmap(Map.Width, Map.Height);  
             mapEngine.OpenAllLayers();  
             mapEngine.DrawStaticLayers(bitmap, GeographyUnit.DecimalDegree);  
             mapEngine.DrawDynamicLayers(bitmap, GeographyUnit.DecimalDegree);  
             mapEngine.CloseAllLayers();  
 
             Map.Image = bitmap;  
         }  
 
         private void ToolBar_ButtonClick(object sender, ToolBarButtonClickEventArgs e)  
         {  
             switch (e.Button.Tag.ToString())  
             {  
                 case "Zoom In":  
                     mapEngine.CurrentExtent.ScaleDown(50);  
                     break;  
                 case "Zoom Out":  
                     mapEngine.CurrentExtent.ScaleUp(50);  
                     break;  
                 case "Full Extent":  
                     mapEngine.CurrentExtent = ExtentHelper.GetDrawingExtent(new RectangleShape(-180.0, 83.0, 180.0, -90.0), Map.Width, Map.Height);  
                     break;  
                 case "Pan Left":  
                     mapEngine.CurrentExtent = ExtentHelper.Pan(mapEngine.CurrentExtent, PanDirection.Left, 20);  
                     break;  
                 case "Pan Right":  
                     mapEngine.CurrentExtent = ExtentHelper.Pan(mapEngine.CurrentExtent, PanDirection.Right, 20);  
                     break;  
                 case "Pan Up":  
                     mapEngine.CurrentExtent = ExtentHelper.Pan(mapEngine.CurrentExtent, PanDirection.Up, 20);  
                     break;  
                 case "Pan Down":  
                     mapEngine.CurrentExtent = ExtentHelper.Pan(mapEngine.CurrentExtent, PanDirection.Down, 20);  
                     break;  
                 default:  
                     break;  
             }  
             DrawImage();  
         }  
 
         private void btnClose_Click(object sender, EventArgs e)  
         {  
             this.Close();  
         }  
 
         private void Map_MouseMove(object sender, MouseEventArgs e)  
         {  
             //Displays the X and Y in screen coordinates.  
             statusStrip1.Items["toolStripStatusLabelScreen"].Text = "X:" + e.X + " Y:" + e.Y;  
 
             //Gets the PointShape in world coordinates from screen coordinates.  
             PointShape pointShape = ExtentHelper.ToWorldCoordinate(mapEngine.CurrentExtent, new ScreenPointF(e.X, e.Y), Map.Width, Map.Height);  
 
             //Displays world coordinates.  
             statusStrip1.Items["toolStripStatusLabelWorld"].Text = "(world) X:" + Math.Round(pointShape.X, 4) + " Y:" + Math.Round(pointShape.Y, 4);  
         }  
     }  
 }