topic Re: SHOW ON MAP MOUSE HOVER - LAT/LONG VALUES in ArcGIS API for Silverlight Questions

SHOW ON MAP MOUSE HOVER - LAT/LONG VALUES

vipulsoni — Mon, 18 Apr 2011 11:05:21 GMT

Hi,

I need help to show lat long on mouse hover on map. I have tried the existing code sample ---

ESRI.ArcGIS.Client.Projection.WebMercator webmercator = new ESRI.ArcGIS.Client.Projection.WebMercator();
                    ESRI.ArcGIS.Client.Geometry.MapPoint latlongpoint = (ESRI.ArcGIS.Client.Geometry.MapPoint)webmercator.FromGeographic(mapPoint);//here I have tried toGeographic also.. for just a try..but still got error ..
                    latlongTextBlock.Text = string.Format("Lat Long: X = {0}, Y = {1}", Math.Round(latlongpoint.Extent.XMin, 4), Math.Round(latlongpoint.Extent.YMin, 4));

But I kept on getting Invalid Spatial Reference error. My map wkid is 32640- wgs84 zone 40N projection.

therefore I added a line -> mapPoint.SpatialReference.WKID = 32640; //but then again got the same spatial reference error..

Then I tried the GEOMETRY SERVICE approach explained in another post in this forum..

     Graphic pointGraphic = new Graphic();
                    pointGraphic.Geometry = mapPoint;
                    pointGraphic.Geometry.SpatialReference = new SpatialReference(32640);
                    IList<Graphic> inG = new List<Graphic>();
                    inG.Add(pointGraphic);

                    GeometryService svcGeometry = new GeometryService(Service_URL.GEOMETRY_SUPREME);
                    svcGeometry.ProjectCompleted += new EventHandler<GraphicsEventArgs>(svcGeometry_ProjectCompleted);
                    svcGeometry.Failed += new EventHandler<TaskFailedEventArgs>(svcGeometry_Failed);
                    SpatialReference sr = new SpatialReference();
                    sr.WKID = 32640;
                    svcGeometry.ProjectAsync(inG, sr);

void svcGeometry_ProjectCompleted(object sender, GraphicsEventArgs e)
        {
            IList<Graphic> results = e.Results;
            Graphic projectedG = results[0]; //should just be one

            //**Code here to build new extent at which to center the map.
            ESRI.ArcGIS.Client.Geometry.MapPoint newpoint = new MapPoint();
            newpoint.X = projectedG.Geometry.Extent.XMin;
            newpoint.Y = projectedG.Geometry.Extent.YMin;

            latlongTextBlock.Text = string.Format("Lat Long: X = {0}, Y = {1}", Math.Round(newpoint.X, 4), Math.Round(newpoint.Y, 4));
        }

But with this instead of getting lat longs ...I get the same results like from the following code sample -

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


My Map/datasets etc are in WGS_1984_UTM_Zone_40N Projection. I dont know where my approach is wrong here , please help...thanks in advance 😞

Re: SHOW ON MAP MOUSE HOVER - LAT/LONG VALUES

ChristopherHill — Mon, 18 Apr 2011 15:41:27 GMT

Your first atttempt with WebMercator. The WebMercator is a client side projection from "web mercator" to Geographic (4326 ) and back. You need to use the GeometryService projection and project 32640 to 4326. Looking at your geometry service projection it appears you are projecting from 32640 to 32640 which is the same thing as you started with. all you should need to do is reaplace the out spatial reference with 4326.

Re: SHOW ON MAP MOUSE HOVER - LAT/LONG VALUES

vipulsoni — Tue, 19 Apr 2011 04:14:32 GMT

Your first atttempt with WebMercator. The WebMercator is a client side projection from "web mercator" to Geographic (4326 ) and back. You need to use the GeometryService projection and project 32640 to 4326. Looking at your geometry service projection it appears you are projecting from 32640 to 32640 which is the same thing as you started with. all you should need to do is reaplace the out spatial reference with 4326.

Thanks Chris..

Re: SHOW ON MAP MOUSE HOVER - LAT/LONG VALUES

BrandonCales — Thu, 07 Jul 2011 14:53:20 GMT

Can anyone share a working code for this? I already have my mouse coordinates showing in xy, but want to give the user an option to change to lat/lon on the fly.

Re: SHOW ON MAP MOUSE HOVER - LAT/LONG VALUES

vipulsoni — Wed, 13 Jul 2011 06:36:05 GMT

Can anyone share a working code for this? I already have my mouse coordinates showing in xy, but want to give the user an option to change to lat/lon on the fly.

This is what I did .

#region Get Lat Longs
        /// <summary>
        /// Map_MouseMove
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="args"></param>
        private void Map_MouseMove(object sender, System.Windows.Input.MouseEventArgs args)
        {
            try
            {
                if (isMapLoaded & isEnabled)
                {
                    System.Windows.Point screenPoint = args.GetPosition(Map);
                    ScreenCoordsTextBlock.Text = string.Format("Screen Coords: X = {0}, Y = {1}",
                        screenPoint.X, screenPoint.Y);

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

                    Graphic pointGraphic = new Graphic();
                    pointGraphic.Geometry = mapPoint;
                    pointGraphic.Geometry.SpatialReference = new SpatialReference(32640);
                    IList<Graphic> inG = new List<Graphic>();
                    inG.Add(pointGraphic);

                    GeometryService svcGeometry = new GeometryService(Service_URL.GEOMETRY_SUPREME);
                    svcGeometry.ProjectCompleted += new EventHandler<GraphicsEventArgs>(svcGeometry_ProjectCompleted);
                    svcGeometry.Failed += new EventHandler<TaskFailedEventArgs>(svcGeometry_Failed);
                    SpatialReference sr = new SpatialReference();
                    sr.WKID = 4326;
                    svcGeometry.ProjectAsync(inG, sr);
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.ToString());
            }
        }

        void svcGeometry_Failed(object sender, TaskFailedEventArgs e)
        {
            MessageBox.Show(e.Error.Message);
        }

        void svcGeometry_ProjectCompleted(object sender, GraphicsEventArgs e)
        {
            IList<Graphic> results = e.Results;
            Graphic projectedG = results[0]; //should just be one

            latlongTextBlock.Text = string.Format("Lat Long: N = {0}, E = {1}", Math.Round(projectedG.Geometry.Extent.XMin, 4), Math.Round(projectedG.Geometry.Extent.YMin, 4));
        }

        private void startcoords_Click(object sender, RoutedEventArgs e)
        {
            if (startcoords.Content.ToString() == "Start Tool")
            {
                isEnabled = true;
                startcoords.Content = "Stop Tool";
            }

            else if (startcoords.Content.ToString() == "Stop Tool")
            {
                isEnabled = false;
                startcoords.Content = "Start Tool";
            }

        }
        #endregion

Re: SHOW ON MAP MOUSE HOVER - LAT/LONG VALUES

BrandonCales — Tue, 26 Jul 2011 14:40:42 GMT

Works perfect....thanks

Re: SHOW ON MAP MOUSE HOVER - LAT/LONG VALUES

BrandonCales — Tue, 26 Jul 2011 15:08:01 GMT

Is there supposed to be a lag when projecting the Lat/Lon, or is it based on hardware?

Re: SHOW ON MAP MOUSE HOVER - LAT/LONG VALUES

IgressT — Tue, 26 Jul 2011 15:29:56 GMT

I think the lag is because it is making a round trip to the server every time there is a map_mouse event...

Re: SHOW ON MAP MOUSE HOVER - LAT/LONG VALUES

ChristopherHill — Fri, 29 Jul 2011 23:30:33 GMT

Yeah, the sample posted by "vipulsoni" is using the geometry service to reproject, which is making a round trip to the server and back.

Re: SHOW ON MAP MOUSE HOVER - LAT/LONG VALUES

LanceCrumbliss — Sat, 30 Jul 2011 16:31:44 GMT

I think the lag is because it is making a round trip to the server every time there is a map_mouse event...

For client side, real time conversion between a decent amount of coordinate systems, check out http://projnet.codeplex.com/

In my Silverlight app, I'm converting back and forth between state plane and geographic coordinates with it and it works perfectly.

Lance

Re: SHOW ON MAP MOUSE HOVER - LAT/LONG VALUES

ChrisBradberry — Fri, 10 Dec 2021 21:06:55 GMT

I used a timer and had it check the mouse move every 5 seconds. Not perfect, but it keeps the lat long display from cycling after the mouse has stopped moving. Here is the code:

        #region Mouse Coordinates on screen
        //get the coordinates to show on the menu bar

        System.Windows.Threading.DispatcherTimer mouseTimer = new System.Windows.Threading.DispatcherTimer();
        ESRI.ArcGIS.Client.Geometry.MapPoint mapPoint; //initiate a map point to get the screen map point

        private void ArcGISTiledMapServiceLayer_Initialized(object sender, EventArgs e)
        {
            //Start the timer 
            mouseTimer.Interval = new TimeSpan(0, 0, 0, 0, 500); // 500 Milliseconds = 1/2 second
            mouseTimer.Tick += new EventHandler(mouseTimer_Tick);

            mouseTimer.Start();

            Map.MouseMove += new System.Windows.Input.MouseEventHandler(MyMap_MouseMove);

        }

        void mouseTimer_Tick(object sender, EventArgs e)
        {
            double mouseX;
            double mouseY;

            if (mapPoint != null)
            {
                Graphic mouseGraphic = new Graphic();

                mouseX = mapPoint.X;
                mouseY = mapPoint.Y;
                mouseGraphic.Geometry = mapPoint;

                  GeometryService latlonService = new GeometryService("http://<server>/ArcGIS/rest/services/Geometry/GeometryServer");
                latlonService.ProjectCompleted += new EventHandler<GraphicsEventArgs>(latlonService_ProjectCompleted);
                latlonService.Failed += new EventHandler<TaskFailedEventArgs>(latlonService_Failed);
                SpatialReference sr = new SpatialReference();
                sr.WKID = 4326;
                IList<Graphic> inG = new List<Graphic>();
                inG.Add(mouseGraphic);

                latlonService.ProjectAsync(inG, sr);
            }
        }


        private void MyMap_MouseMove(object sender, System.Windows.Input.MouseEventArgs args)
        {
            if (Map.Extent != null)
            {
                Graphic mouseGraphic = new Graphic();

                System.Windows.Point screenPoint = args.GetPosition(Map);
                mapPoint = Map.ScreenToMap(screenPoint);
            }
        }

        void latlonService_Failed(object sender, TaskFailedEventArgs e)
        {
            MessageBox.Show(e.Error.Message + "Latitude Longitude Service Failed");
        }

        void latlonService_ProjectCompleted(object sender, GraphicsEventArgs e)
        {
            IList<Graphic> results = e.Results;
            string mouseCoords = "Latitude: " + Utilities.DDtoDMS(results[0].Geometry.Extent.YMax, false);
            mouseCoords += ", Longitude: " + Utilities.DDtoDMS(results[0].Geometry.Extent.XMax, false);
            LatLongText.Text = mouseCoords;

        }
        #endregion

Re: SHOW ON MAP MOUSE HOVER - LAT/LONG VALUES

DeeptiVB — Thu, 10 Dec 2015 22:36:49 GMT

Hope this helps someone. Was not able to get it to work by using projections. Found an old archived forum thread which helped me convert to lat long mathematically. Here's the code below.

	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);
	if (MyMap.WrapAroundIsActive)
	mapPoint = ESRI.ArcGIS.Client.Geometry.Geometry.NormalizeCentralMeridian(mapPoint) as ESRI.ArcGIS.Client.Geometry.MapPoint;

	Double longi = mapPoint.X;
	Double lati = mapPoint.Y;
	Double pi = 3.14159267;
	Double magicnum = 6356752.3142;
	Double radtodeg = 57.295779513082322;

	Double latitude = new Double();
	Double longitude = new double();

	latitude = radtodeg * ((2 * Math.Atan(Math.Exp(lati / magicnum))) - (pi / 2));
	longitude = radtodeg * (longi / magicnum);

	StatusTextBlock.Text = string.Format("Map Coords: X = {0}, Y = {1}",
	Math.Round(latitude, 4), Math.Round(longitude, 4));

	}
	}