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ThinkGeo Cloud
ThinkGeo UI Controls
ThinkGeo Open Source
Help and Support
External Resources
using System; using System.Collections.Generic; using System.Linq; using System.Windows.Forms; namespace SphericalMercatorProjectionAdjustment { 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.Windows.Forms; using ThinkGeo.MapSuite.Core; using ThinkGeo.MapSuite.DesktopEdition; namespace SphericalMercatorProjectionAdjustment { public partial class TestForm : Form { public TestForm() { InitializeComponent(); } private void TestForm_Load(object sender, EventArgs e) { winformsMap1.MapUnit = GeographyUnit.Meter; winformsMap1.CurrentExtent = new RectangleShape(-183470, 7119187, -177290, 7115400); winformsMap1.BackgroundOverlay.BackgroundBrush = new GeoSolidBrush(GeoColor.FromArgb(255, 198, 255, 255)); //Displays the World Map Kit as a background. GoogleMapsOverlay googleMapsOverlay = new GoogleMapsOverlay(); winformsMap1.Overlays.Add(googleMapsOverlay); //Sets the projection to go from British National Grid to Spherical Mercator used by Google Map. Proj4Projection proj4 = new Proj4Projection(); //British National Grid //http://www.spatial-reference.org/ref/epsg/27700/ proj4.InternalProjectionParametersString = Proj4Projection.GetEpsgParametersString(27700); //Spherical Mercator projection used by Google Map. //GetGoogleMapParametersString returns "+proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0 +y_0=0 +k=1.0 +units=m +no_defs" proj4.ExternalProjectionParametersString = Proj4Projection.GetGoogleMapParametersString(); ShapeFileFeatureLayer shapefileFeatureLayer = new ShapeFileFeatureLayer( @"..\..\data\railways_leeds.shp"); shapefileFeatureLayer.ZoomLevelSet.ZoomLevel01.DefaultLineStyle = LineStyles.Railway1; shapefileFeatureLayer.ZoomLevelSet.ZoomLevel01.ApplyUntilZoomLevel = ApplyUntilZoomLevel.Level20; //Sets the projection. You can notice that the railways layer is offset about one hundred meters to the east. shapefileFeatureLayer.FeatureSource.Projection = proj4; LayerOverlay staticOverlay = new LayerOverlay(); staticOverlay.Layers.Add("Railways", shapefileFeatureLayer); winformsMap1.Overlays.Add("StaticOverlay", staticOverlay); winformsMap1.Refresh(); } private void btnAdjust_Click(object sender, EventArgs e) { //The purpose of this function is to adjust the inaccuracy that occurs in many cases from using straight GetGoogleMapParameters function when going //from ellipsoid datum to spherical datum. Proj4Projection proj4 = new Proj4Projection(); proj4.InternalProjectionParametersString = Proj4Projection.GetEpsgParametersString(27700); //From the original Spherical Mercator projection string, we add the parameter +nadgrids=@null so that no grid shift occurs when going from airy ellipsoid based datum //to Spherical datum used by Spherical Mercator projection. proj4.ExternalProjectionParametersString = "+proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0 +y_0=0 +k=1.0 +units=m +nadgrids=@null +no_defs"; ShapeFileFeatureLayer shapefileFeatureLayer = (ShapeFileFeatureLayer)winformsMap1.FindFeatureLayer("Railways"); shapefileFeatureLayer.FeatureSource.Projection = proj4; proj4.Open(); winformsMap1.Refresh(winformsMap1.Overlays["StaticOverlay"]); btnAdjust.Enabled = false; } private void winformsMap1_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(winformsMap1.CurrentExtent, new ScreenPointF(e.X, e.Y), winformsMap1.Width, winformsMap1.Height); //Displays world coordinates. statusStrip1.Items["toolStripStatusLabelWorld"].Text = "(world) X:" + Math.Round(pointShape.X, 4) + " Y:" + Math.Round(pointShape.Y, 4); } private void btnClose_Click(object sender, EventArgs e) { this.Close(); } } }