using System;
using System.Collections.ObjectModel;
using System.Drawing;
using System.Windows.Forms;
using ThinkGeo.MapSuite.Core;
namespace DatumTransformation
{
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(-9.1386,38.7187,-9.1217,38.7091), 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();
mapEngine.StaticLayers.Add(worldMapKitLayer);
//InMemoryFeatureLayer for displaying the points.
InMemoryFeatureLayer inMemoryFeatureLayer = new InMemoryFeatureLayer();
inMemoryFeatureLayer.Open();
inMemoryFeatureLayer.Columns.Add(new FeatureSourceColumn("Datum", "string", 20));
inMemoryFeatureLayer.Close();
inMemoryFeatureLayer.ZoomLevelSet.ZoomLevel01.DefaultPointStyle = PointStyles.CreateSimpleCircleStyle(GeoColor.StandardColors.DarkGreen,
10, GeoColor.StandardColors.Black, 2);
inMemoryFeatureLayer.ZoomLevelSet.ZoomLevel01.DefaultTextStyle = TextStyles.CreateSimpleTextStyle("Datum", "Arial", 10, DrawingFontStyles.Bold,
GeoColor.StandardColors.Black,10,0);
inMemoryFeatureLayer.ZoomLevelSet.ZoomLevel01.ApplyUntilZoomLevel = ApplyUntilZoomLevel.Level20;
//We are adding the points for ED50 and WGS84. You have to understand that they are actually the same points except that two different
//datums are used.
//The point is originatly in degrees with ED50 datum. We display it to show how offset it is compared to the same point in degrees with WGS84 datum
PointShape ED50pointShape = new PointShape(-9.1302509553484654, 38.714824991881208);
Feature ED50feature = new Feature(ED50pointShape);
ED50feature.ColumnValues.Add("Datum", "ED50");
inMemoryFeatureLayer.InternalFeatures.Add(ED50feature);
//We take the same point in ED50 datum and apply Datum trasformation to it so that it is using WGS84 as for the World Map Kit.
//So, the point in WGS84 is the corrected point from ED50 so that it matched World Map Kit.
//Notice that for datum transformation, the same API is used where you set the parameters for InternalProjectionParameters and externalProjectionParameters.
//To go from ED50 datum to WGS84 datum so that the point matches the projection of the map.
ManagedProj4Projection proj4 = new ManagedProj4Projection();
//Degrees ED50 for internal projection
//http://www.spatialreference.org/ref/epsg/62306405/ (for reference)
//http://en.wikipedia.org/wiki/ED50 (for further information)
proj4.InternalProjectionParametersString = "+proj=longlat +ellps=intl +towgs84=-157.89,-17.16,-78.41,2.118,2.697,-1.434,-1.1097046576093785 +no_defs";
//WGS84 projection (datum) for external projection
//http://www.spatialreference.org/ref/epsg/4326/ (for reference)
//http://en.wikipedia.org/wiki/WGS84 (for further information)
proj4.ExternalProjectionParametersString = ManagedProj4Projection.GetEpsgParametersString(4326);
proj4.Open();
Vertex WGS84vertex = proj4.ConvertToExternalProjection(ED50pointShape.X, ED50pointShape.Y);
proj4.Close();
Feature WGS84feature = new Feature(new PointShape(WGS84vertex.X, WGS84vertex.Y));
WGS84feature.ColumnValues.Add("Datum", "WSG84");
inMemoryFeatureLayer.InternalFeatures.Add(WGS84feature);
mapEngine.DynamicLayers.Add("Points", inMemoryFeatureLayer);
//Displays Scale Bar to how offset the same point is based on the datum.
//You can notice that the ED50 point is offset about 200 meters to the north east compared to WGS84.
//When doing a datum transformation, the difference is slight, usually a few meters. It can be thought as merely a correction.
//When changing projection to the data, though, the difference is huge. We change completely of coordinate system and the same
//point cannot be displayed on the same map.
ScaleBarAdornmentLayer scaleBarAdornmentLayer = new ScaleBarAdornmentLayer();
scaleBarAdornmentLayer.UnitFamily = UnitSystem.Metric;
scaleBarAdornmentLayer.Location = AdornmentLocation.LowerLeft;
mapEngine.AdornmentLayers.Add(scaleBarAdornmentLayer);
DrawImage();
}
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.DrawAdornmentLayers(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);
}
}
}