[GIS] Coordinate conversion – Lat Long to State Plane, ArcServer-Silverlight

ccoordinate systemcoordinatesweb-mercator

I am trying to project a Lat/Long value I get from a table to a x/y value that I can use to plot a graphic.

I have seen one way to do this may be to use something like this:

feature.Geometry = mercator.FromGeographic(new MapPoint(lat, lon));
feature.Symbol = LayoutRoot.Resources["TRUCK"] as ESRI.ArcGIS.Client.Symbols.Symbol;
graphicsLayer.Graphics.Add(feature);

However my graphics aren't showing up overlapping my tiled basemap service. I tried the mercator.FromGeographic and Mercator.ToGeographic with unsuccessful results.

My Lat/Long value: 37.1223133333333,-93.27893
Mercator.FromGeographic converted value: X=-10382795.4374339, Y=4469266.40579955, WKID=102100
Mercator.ToGeographic converted value: X=-0.000837860806483038, Y=0.000334317600035687, WKID=4326

Neither of these coordinates put my graphics in the correct location. It should be closer to something like this: X=1424565.77, Y=501970.98. I am trying to learn more about coordinate systems, conversions between systems, etc. Any thoughts on what I can try next?

I am still in the beginner phase of learning programming so thanks for your help. Would you have this as a standalone class in your project?

Here is the code I have so far:

C#

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;
using ESRI.ArcGIS.Client;
using ESRI.ArcGIS.Client.Geometry;
using ESRI.ArcGIS.Client.Symbols;
using System.Runtime.Serialization;
using ESRI.ArcGIS.Client.Tasks;
using System.Windows.Threading;
using ESRI.ArcGIS.Client.Bing;

namespace TruckGPS_Test
{
    public partial class MainPage : UserControl
    {
        //private static ESRI.ArcGIS.Client.Projection.WebMercator mercator = new ESRI.ArcGIS.Client.Projection.WebMercator();

        public MainPage()
        {
            InitializeComponent();
            //AddMarkerGraphics();

            QueryTask queryTaskTruckGPS = new QueryTask("http://gisaprd/ArcGIS/rest/services/TruckGPS/MapServer/8");
            queryTaskTruckGPS.ExecuteCompleted += QueryTask_ExecuteCompletedTruckGPS;
            ESRI.ArcGIS.Client.Tasks.Query queryTruckGPS = new ESRI.ArcGIS.Client.Tasks.Query();
            queryTruckGPS.OutFields.Add("*");
            queryTruckGPS.ReturnGeometry = false;
            queryTruckGPS.Where = "1=1";
            queryTaskTruckGPS.ExecuteAsync(queryTruckGPS, "initial");

            //This timer updates the outage feature count after a 30 second wait
            System.Windows.Threading.DispatcherTimer myDispatcherTimer = new System.Windows.Threading.DispatcherTimer();
            myDispatcherTimer.Interval = new TimeSpan(0, 0, 0, 10, 0);
            myDispatcherTimer.Tick += new EventHandler(Each_Tick);
            myDispatcherTimer.Start();
        }

        public void Each_Tick(object o, EventArgs sender)
        {
            QueryTask queryTaskTruckGPS = new QueryTask("http://gisaprd/ArcGIS/rest/services/TruckGPS/MapServer/8");
            queryTaskTruckGPS.ExecuteCompleted += QueryTask_ExecuteCompletedTruckGPS;
            ESRI.ArcGIS.Client.Tasks.Query queryTruckGPS = new ESRI.ArcGIS.Client.Tasks.Query();
            queryTruckGPS.OutFields.Add("*");
            queryTruckGPS.ReturnGeometry = false;
            queryTruckGPS.Where = "1=1";
            queryTaskTruckGPS.ExecuteAsync(queryTruckGPS, "initial");
        }

        private void QueryTask_ExecuteCompletedTruckGPS(object sender, ESRI.ArcGIS.Client.Tasks.QueryEventArgs args)
        {
            //If Counter isn't working check the web service, make sure the table is added to the map service

            FeatureSet featureSet = args.FeatureSet;
            GraphicsLayer graphicsLayer = MyMap.Layers["TruckGPS"] as GraphicsLayer;
            graphicsLayer.ClearGraphics();
            if (featureSet != null && featureSet.Features.Count > 0)
            {
                ////Check the system time and subtract the time amount wanted from the last gps systime read for movement or idle truck
                //System.DateTime dTime = DateTime.Now;
                //// tSpan is 0 days, 0 hours, 0 minutes, and 0 seconds.
                //System.TimeSpan tSpan = new System.TimeSpan(0, 1, 0, 0);
                //System.DateTime result = dTime - tSpan;
                foreach (ESRI.ArcGIS.Client.Graphic feature in featureSet.Features)
                {
                    if ((feature.Attributes["LONGITUDE"] != null) && (feature.Attributes["LATITUDE"] != null))
                    //&& (feature.Attributes["S"])
                    {
                        var Machine_Name = feature.Attributes["MACHINE_NAME"].ToString();
                        var User_Name = feature.Attributes["USER_NAME"].ToString();
                        double lat = Convert.ToDouble(feature.Attributes["LONGITUDE"]);
                        double lon = Convert.ToDouble(feature.Attributes["LATITUDE"]);

                        feature.Geometry = new MapPoint(lat, lon);
                        //if (User_Name == "CU656")
                        //{
                        //feature.Geometry = mercator.ToGeographic(new MapPoint(lat, lon));
                        feature.Symbol = LayoutRoot.Resources["TRUCK"] as ESRI.ArcGIS.Client.Symbols.Symbol;
                        graphicsLayer.Graphics.Add(feature);
                        //}
                        //else
                        //{
                        //    feature.Symbol = LayoutRoot.Resources["RedMarkerSymbol"] as ESRI.ArcGIS.Client.Symbols.Symbol;
                        //    graphicsLayer.Graphics.Add(feature);
                        //}
                    }
                }
                { (MyMap.Layers["TruckGPS"] as GraphicsLayer).Refresh(); };
            }
            else
            {
                graphicsLayer.ClearGraphics();
                //MessageBox.Show("No features returned from query");
            }
        }
        private void MyMap_MouseMove(object sender, System.Windows.Input.MouseEventArgs args)
        {
            if (MyMap.Extent != null)
            {
                System.Windows.Point screenPoint = args.GetPosition(MyMap);
                ScreenCoordsTextBlock.Text = string.Format("Screen Coords: X = {0}, Y = {1}",
                    screenPoint.X, screenPoint.Y);

                ESRI.ArcGIS.Client.Geometry.MapPoint mapPoint = MyMap.ScreenToMap(screenPoint);
                if (MyMap.WrapAroundIsActive)
                    mapPoint = ESRI.ArcGIS.Client.Geometry.Geometry.NormalizeCentralMeridian(mapPoint) as ESRI.ArcGIS.Client.Geometry.MapPoint;
                MapCoordsTextBlock.Text = string.Format("Map Coords: X = {0}, Y = {1}",
                    Math.Round(mapPoint.X, 4), Math.Round(mapPoint.Y, 4));
            }
        } 
    }
}

At what point would I use the geometry service or call the class you stubbed out?

Best Answer

You can use the ArcGIS Server REST API out-of-the-box Geometry Service, which has a Project operation, to project a coordinate pair, and then create a graphic from it. The Geometry Service is included in the ESRI Silverlight API as the GeometryService class.

If you haven't your own ArcGIS Server, perhaps you can try the ESRI-published sample servers.

Example class hacked out of one of mine:

using System;
using System.Net;
using ESRI.ArcGIS.Client;
using ESRI.ArcGIS.Client.Geometry;
using ESRI.ArcGIS.Client.Tasks;
using System.Collections.Generic;

namespace YabaDabaDoo
{
  /// <summary>
  /// A Service for projecting a point to another coordinate system
  /// and return its coordinates. This service can only operate on
  /// points.
  /// </summary>
  public class ProjectionService
  {
    #region Private/Protected Fields
    private GeometryService _gService = null;
    private SpatialReference _tosr = null;
    #endregion

    public ProjectionService(string gserveUrl, int toSrid)
    {     
      //gserveUrl should be like: http://sampleserver1.arcgisonline.com/ArcGIS/rest/services/Geometry/GeometryServer
      //if you don't know your SRID, check the lists at: http://resources.arcgis.com/en/help/rest/apiref/usingspatialreferences.html
      _gService = new GeometryService(gserveUrl);
      _tosr = new SpatialReference(toSrid);
      _gService.ProjectCompleted += new EventHandler<GraphicsEventArgs>(_gService_ProjectCompleted);
      _gService.Failed += new EventHandler<TaskFailedEventArgs>(_gService_Failed);
    }

    /// <summary>
    /// This does the real work of the service. In this case, the input SR is that of the graphic.
    /// </summary>
    public void ProjectPoint(Graphic editGraphic)
    {
      try
      {
        //check that the geometry is a point
        if (editGraphic.Geometry is MapPoint)
        {
          _gService.ProjectAsync(new List<Graphic>() { new Graphic() { Geometry = Geometry.Clone(editGraphic.Geometry) } }, _tosr);
        }
        else
        {
          // can't do this
        }
      }
      catch (Exception e)
      {
        //TODO: do something sensible
      }
    }
    #endregion

    #region Private/Protected methods - GeometryService event handlers
    void _gService_ProjectCompleted(object sender, GraphicsEventArgs e)
    {
      MapPoint p = e.Results[0].Geometry as MapPoint;

      //TODO: do something with p
    }

    private void _gService_Failed(object sender, TaskFailedEventArgs e)
    {
      //TODO: do something sensible
    }
    #endregion
  }
}

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Since you have ArcGIS 10.1 available, it would be easy to import your current data in excel format, plot the XY coordinates in the current coordinate system, reproject your points to your desired coordinate system, and then export the data back to a new spreadsheet.

To do this, follow these steps:

1.) Add your existing spreadsheet to ArcMap

2.) Right click your spreadsheet in the table of contents and select "Display XY Data"

Choose the appropriate fields for your X and Y coordinates
Under "Coordinate System of Input Coordinates" select "Edit..." and choose the correct coordinate system.

3.) Once your points are plotted, right click your plotted data in the table of contents and select data -> Export Data. Save the plotted points to a shapefile and add it to your map.

4.) Reproject the shapefile to the desired projection.

5.) In the Data Management -> Features toolbox, run Add XY Coordinates on your newly projected shapefile. You may have to rename your existing XY fields if they are named POINT_X and POINT_Y, as these are the field names the tool uses. This will add the XY coordinates in the new coordinate system to your attribute table.

6.) Open the attribute table of your shapefile, under table options select Export. Choose an appropriate format and location to save your spreadsheet to.

Voila, you have a new spreadsheet with projected XY data. If your ultimate goal is just to get the data into shapefile format in the correct projection, just do steps 1-4.

[GIS] VB.net Converting UTM to Lat/Lon (State Plane with WKID) – ArcGis

For those interested I've managed to get this working, I'm converting from MGA meters to a local map grid projection, also in meters.

private Esri.ArcGISRuntime.Geometry.MapPoint ConvertToLocalMapGridCoords(Esri.ArcGISRuntime.Geometry.MapPoint sourceMapPoint, string projectionFile)
{
    var wkTextDest = System.IO.File.ReadAllText(projectionFile);

    var projectionConverter = new Esri.ArcGISRuntime.Geometry.ProjectionConverter();
    var result = projectionConverter.Convert(sourceMapPoint, typeof(MapPoint), wkTextDest, System.Globalization.CultureInfo.InvariantCulture);

    return (Esri.ArcGISRuntime.Geometry.MapPoint)result;
}

I'm calling it using: (You will most likely be doing something completely different here!)

const int wkidSource = 102100;
var coordPoint = newMapControl.ScreenPointToCoordPoint(e.Location);

var mouseMapPoint = Esri.ArcGISRuntime.Geometry.ConvertCoordinate.FromDecimalDegrees(string.Format("{0},{1}", coordPoint.GetY(), coordPoint.GetX()), new Esri.ArcGISRuntime.Geometry.SpatialReference(wkidSource));

var convertedMapPoint = ConvertToLocalMapGridCoords(mouseMapPoint, @"C:\abc\xyz.prj");

I'm creating a spacial reference from a well known text (ESRI Projection File .prj).

Note: coordPoint.GetY(), coordPoint.GetX() are just Decimal latitudes and longitudes respectively.

Best Answer

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