Is there a way to project the coordinates without using geometry service?

[DanDong]

Hi guys,

I am using mouse_move event to show the coordinates of the position. Just like this sample: http://help.arcgis.com/en/webapi/silverlight/samples/start.htm#MouseCoords

But the projection of the maps in the map service is Transverse_Mercator and I want to display the coordinates in lat/long. I know geometry service supports projection task and I tied this method in my codes. But since we all move mouse very quickly and frequently and every move needs projection, this method really slows down the response time...

I really would like to know whether there is a api or method to do this without projection every mousemove point nor kill the performance. Any thoughts or clues? Thank you!!

Below are my codes:

private void MyMap_MouseMove(object sender, System.Windows.Input.MouseEventArgs args)
        {
            if (MyMap.Extent != null)
            {
                System.Windows.Point screenPoint = args.GetPosition(MyMap);
                ESRI.ArcGIS.Client.Geometry.MapPoint mapPoint = MyMap.ScreenToMap(screenPoint);
                //MapCoordsTextBlock.Text = string.Format("Map Coords: X = {0}, Y = {1}",
                    //Math.Round(mapPoint.X, 4), Math.Round(mapPoint.Y, 4));

                //MapPoint inputMapPoint = new MapPoint(x, y, new SpatialReference(4326));

                //use geometryservice's project utility
                //GeometryService geometryService = new GeometryService("http://rmms-dev.atlas.illinois.edu/ArcGIS/rest/services/Geometry/GeometryServer");
                //geometryService.ProjectCompleted += MouseCoordinate_geometryService_ProjectCompleted;
                //geometryService.Failed += GeometryService_Failed;
                //geometryService.ProjectAsync(new List<Graphic>() { new Graphic() { Geometry = mapPoint } }, new SpatialReference(4326), mapPoint);
            }
        }

void MouseCoordinate_geometryService_ProjectCompleted(object sender, GraphicsEventArgs e)
        {
            Graphic resultGraphic = e.Results[0];
            MapPoint resultMapPoint = resultGraphic.Geometry as MapPoint;
            MapCoordsTextBlock.Text = string.Format("Map Coords: X = {0}, Y = {1}",
                    Math.Round(resultMapPoint.X, 4), Math.Round(resultMapPoint.Y, 4));
        }

[IgressT]

Don't know if this will work for you but you can take a look at it...

http://projnet.codeplex.com/

[BrandonCopeland]

ESRI.ArcGIS.Client.Bing.Transform does just that

[DanDong]

Don't know if this will work for you but you can take a look at it...

http://projnet.codeplex.com/

Hey Doc, thanks a lot! From the live sample I think that's what I want (convert coordinates from UTM to lat/long). But it looks like there is no readme in it. I can only add the dll file from XX.Web --Add reference. If I try to add it from XX--Add reference, it says:" You cannot add a reference to ProjNet.dll as it was not build against the silverlight runtime. Silverlight projects will only work with silverlight assemblies"

Any guessing for that? Thank you:)

[DanDong]

ESRI.ArcGIS.Client.Bing.Transform does just that

Hi Brandon, thank you for your suggestion. I checked this one, but this is only for converting from between webmercator (WKID=102100) and geographic WGS84. And I would like to convert UTM to geographic WGS84.

[DanielWalton]

ProjNet has a Silverlight library too. Just hunt around, it's in there.

[IgressT]

Hi Brandon, thank you for your suggestion. I checked this one, but this is only for converting from between webmercator (WKID=102100) and geographic WGS84. And I would like to convert UTM to geographic WGS84.

I was able to do utm from/to geographic using Proj.Net you can do it... let me know if you need a sample...

[DanDong]

ProjNet has a Silverlight library too. Just hunt around, it's in there.

Hey Daniel, thank you! I found this: Is it the one you mentioned above? http://projnet.codeplex.com

[DanDong]

I was able to do utm from/to geographic using Proj.Net you can do it... let me know if you need a sample...

Hi Doc, I really appreciate that you would share a sample 🙂 This task really burns my head...
BTW: In the weblink you gave me I download the dll file, but I cannot add this reference to the project reference, I can only add it to project's web reference. Was it normal or just I did some mistake. ..Thank you!

[IgressT]

I never tested the following code how accurate it is... it was just a part of my dirty prototype... so would recommend test it...
I followed the sample given on ProjNet

    /// <summary>
    /// Class that performs conversions using the ProjNet library.
    /// </summary>
    public class CoordinateConversion
    {
        /// <summary>
        /// Function that converts UTM x,y to lat long.
        /// </summary>
        /// <param name="x">UTM x coordinate.</param>
        /// <param name="y">UTM y coordinate.</param>
        /// <param name="zone">The zone of the UTM.</param>
        /// <param name="zoneisnorth">If Zone is north.</param>
        /// <returns>The lat long value.</returns>
        public static Point UTMtoLATLONG(double x, double y, int zone, bool zoneisnorth)
        {
            System.Windows.Point p = new System.Windows.Point(x, y);

            CoordinateTransformationFactory ctfac = new CoordinateTransformationFactory();
            ICoordinateSystem wgs84geo = ProjNet.CoordinateSystems.GeographicCoordinateSystem.WGS84;
            ICoordinateSystem utm = ProjNet.CoordinateSystems.ProjectedCoordinateSystem.WGS84_UTM(zone, zoneisnorth);
            ICoordinateTransformation trans = ctfac.CreateFromCoordinateSystems(wgs84geo, utm);

            IMathTransform test = trans.MathTransform.Inverse();
            Point pxy = test.Transform(p);

            return pxy;
        }

        /// <summary>
        /// Lat long to UTM.
        /// </summary>
        /// <param name="latitude">The longitude value.</param>
        /// <param name="longitude">The latitude value.</param>
        /// <param name="zone">The UTM Zone.</param>
        /// <param name="zoneisnorth">If the UTM zone is north.</param>
        /// <returns>The UTM X and Y values.</returns>
        public static Point LATLONGtoUTM(double latitude, double longitude, int zone, bool zoneisnorth)
        {
            System.Windows.Point pointGeo = new Point(longitude, latitude);

            // Transform to UTM - Calculates UTM coordinates and zone
            CoordinateTransformationFactory ctfac = new CoordinateTransformationFactory();
            ICoordinateSystem wgs84geo = ProjNet.CoordinateSystems.GeographicCoordinateSystem.WGS84;
            int calculatedZone = (int)Math.Ceiling((pointGeo.X + 180) / 6);
            ICoordinateSystem utm = ProjNet.CoordinateSystems.ProjectedCoordinateSystem.WGS84_UTM(calculatedZone, pointGeo.Y > 0);
            ICoordinateTransformation trans = ctfac.CreateFromCoordinateSystems(wgs84geo, utm);
            Point pointUtm = trans.MathTransform.Transform(pointGeo);
            
            // If calculated zone is not same as the supplied zone then convert the calculated UTM to the supplied UTM zone
            if (calculatedZone != zone)
            {
                // The original UTM zone that the map is in
                ICoordinateSystem utmto = ProjNet.CoordinateSystems.ProjectedCoordinateSystem.WGS84_UTM(zone, zoneisnorth);
                
                // The UTM of calculated zone
                ICoordinateSystem utmfrom = ProjNet.CoordinateSystems.ProjectedCoordinateSystem.WGS84_UTM(calculatedZone, zoneisnorth);

                trans = ctfac.CreateFromCoordinateSystems(utmfrom, utmto);
                pointUtm = trans.MathTransform.Transform(pointUtm);
            }

            return pointUtm;
        }
    }