topic Re: Displaying coordinates on MAP in ArcGIS API for Flex Questions

Displaying coordinates on MAP

AshishYadav — Wed, 21 May 2014 06:13:47 GMT

Greetings to all,

I had been working with Google Maps for displaying coordinates till now, but then came across ARCGIS and was exited to work with this. Started a day or two ago, came across a strange behavior and i am desperate to get a work around on this.

The coordinates (30.7764803800,76.0161244300) points out to place X in INDIA where as the same represents a place in AFRICA.

Looking forward to some assistance on this.

Thanks

Re: Displaying coordinates on MAP

AaronNash1 — Wed, 21 May 2014 11:15:12 GMT

if you posted your code it might be easier for someone to help

Re: Displaying coordinates on MAP

KomanDiabate — Wed, 21 May 2014 15:00:44 GMT

You should still post your code, but I think you are flip-flopping your coordinates. (See attachment).

[ATTACH=CONFIG]33969[/ATTACH]

Re: Displaying coordinates on MAP

AshishYadav — Thu, 22 May 2014 04:00:23 GMT

Hi @nasha001 @kdiabate64,

This is what i have written in the code:

var myGraphicPoint:Graphic = new Graphic(new MapPoint(30.7764803800, 76.0161244300, new SpatialReference(4326)));
myGraphicPoint.symbol = pictureMarker;
myGraphicsLayer.add(myGraphicPoint);

The X&Y here are static values passed as shown in the attachment shared by @kdiabate64.
I saw the attachment shared by @hdiabate64 and that is what Google Map shows at my end too but its the way around as shown in the attachment share below using ARCGIS.

Looking forward to hear from you.

Thanks

Re: Displaying coordinates on MAP

PaulHastings1 — Thu, 22 May 2014 08:43:52 GMT

google's points are constructed latitude, longitude (y,x) vs ESRI's longitude, latitude (x,y). kdiabate64
is correct, your coords are swapped.

Re: Displaying coordinates on MAP

AshishYadav — Fri, 23 May 2014 03:20:42 GMT

Hi Paul,

Swapping the coords to

var myGraphicPoint:Graphic = new Graphic(new MapPoint(76.0161244300, 30.7764803800, new SpatialReference(4326)));
myGraphicPoint.symbol = pictureMarker;
myGraphicsLayer.add(myGraphicPoint);

doesn't changes anything for me... I wonder if everything else is correct or not..

Looking forward to hear from you.

Thanks

Re: Displaying coordinates on MAP

AaronNash1 — Fri, 23 May 2014 12:02:02 GMT

I created a quick app and attached is a screen shot, I am experiencing the same behavior as you. The coordinates are not in the same projection as your basemap and it is causing map point be displayed in Africa. Here is some code for reprojecting a mappoint into the same coordinate system as the basemap, this should work with any basemap.

<s:Application xmlns:fx="http://ns.adobe.com/mxml/2009"       xmlns:s="library://ns.adobe.com/flex/spark"       xmlns:esri="http://www.esri.com/2008/ags">  <s:layout>   <s:VerticalLayout horizontalAlign="center"/>  </s:layout>  <fx:Script>   <![CDATA[    import com.esri.ags.Graphic;    import com.esri.ags.Map;    import com.esri.ags.SpatialReference;    import com.esri.ags.events.GeometryServiceEvent;    import com.esri.ags.geometry.MapPoint;    import com.esri.ags.symbols.SimpleMarkerSymbol;    import com.esri.ags.tasks.GeometryService;    import com.esri.ags.tasks.supportClasses.ProjectParameters;         //create the mappoint using the lat and long    private function createPoint():void     {      var testPoint:MapPoint = new MapPoint(76.0161244300, 30.7764803800);     //spatial reference of the mappoint     testPoint.spatialReference = new SpatialReference(4326);      var projParams:ProjectParameters = new ProjectParameters();     projParams.geometries = [testPoint];     //reproject to map spatial reference     projParams.outSpatialReference = myMap.spatialReference;     geometryService.project(projParams);         }         //reproject event     private function projectCompleteHandler(event:GeometryServiceEvent):void    {      try     {      // Note: As of version 2.0, GeometryService returns geometries (instead of graphics)            var pt:MapPoint = (event.result as Array)[0]as MapPoint;      var ptGraphic:Graphic = new Graphic(null, new SimpleMarkerSymbol(SimpleMarkerSymbol.STYLE_DIAMOND, 22, 0x009933));      ptGraphic.geometry = pt;       myGraphicsLayer.clear()      myGraphicsLayer.add(ptGraphic);     }     catch (error:Error)     {      //Alert.show(error.toString());     }    }    ]]>  </fx:Script>  <fx:Declarations>   <esri:GeometryService id="geometryService" showBusyCursor="false" projectComplete="projectCompleteHandler(event)"            url="http://sampleserver3.arcgisonline.com/ArcGIS/rest/services/Geometry/GeometryServer"/>  </fx:Declarations>  <s:controlBarLayout>   <s:VerticalLayout gap="10" paddingBottom="7" paddingLeft="10" paddingRight="10" paddingTop="7"/>  </s:controlBarLayout>  <s:controlBarContent>   <s:Button id="btn" click="createPoint()" label="Add some more markers using ActionScript"/>  </s:controlBarContent>  <esri:Map id="myMap" level="2" wrapAround180="true">   <esri:ArcGISTiledMapServiceLayer url="http://server.arcgisonline.com/ArcGIS/rest/services/World_Street_Map/MapServer"/>   <esri:GraphicsLayer id="myGraphicsLayer"/>  </esri:Map> </s:Application>

Also built into the ESRI Flex API is the ability to translate Latitude and Longitude into webmercator without having to make a call to a geometry service. If you are using the ESRI basemaps (which are in webmercator) then here is the code to create a mappoint that will put the point where it is supposed to go

var testPoint:WebMercatorMapPoint = new WebMercatorMapPoint(76.0161244300, 30.7764803800);

hope that helps

Re: Displaying coordinates on MAP

SamarthGupta — Fri, 10 Dec 2021 22:54:02 GMT

If i have to display polylines using the same co-ordinates then how will i provide my co-ordinates to polyline mappoint

This is the general way of placing polyline on ArcGIS map:

myPolyline = new Polyline([[new mapPoint(x, y), new mapPoint(x, y)]], new SpatialReference(4326));
var myGraphicLine:Graphic = new Graphic(myPolyline);
myGraphicLine.symbol = new SimpleLineSymbol(SimpleLineSymbol.STYLE_SOLID, 0xFF0000, 1.0, 4);
myGraphicsLayer.add(myGraphicLine);

Re: Displaying coordinates on MAP

AshishYadav — Thu, 29 May 2014 11:25:20 GMT

Hi,

@nasha001 that was quick and awesome, sorry for replying late but it did work just smooth as i wanted it to be.
However, i am facing another concern and seeking your or everybody's help again.

How can i connect two map points on the MAP with a polyline(as its done in Google Maps).
The following code is what i had tried:

myPolyline = new Polyline([[new mapPoint(x, y), new mapPoint(x, y)]], new SpatialReference(4326));
var myGraphicLine:Graphic = new Graphic(myPolyline);
myGraphicLine.symbol = new SimpleLineSymbol(SimpleLineSymbol.STYLE_SOLID, 0xFF0000, 1.0, 4);
myGraphicsLayer.add(myGraphicLine);

Thanks

Re: Displaying coordinates on MAP

AaronNash1 — Fri, 10 Dec 2021 22:54:05 GMT

where it says new MapPoint, just put in your x and y like below. There is a good sample here

var myPolyline:Polyline = new Polyline(
                    [[
                     new MapPoint(-1726185, 9543036),
                     new MapPoint(34923, 6920940),
                     new MapPoint(1874303, 6255632),
                     new MapPoint(1835168, 6255632),
                     new MapPoint(1913439, 6138225)
                     ]], new SpatialReference(102100));
                var myGraphicLine:Graphic = new Graphic(myPolyline);
                myGraphicLine.symbol = new SimpleLineSymbol(SimpleLineSymbol.STYLE_DASH, 0xDD2222, 1.0, 4);
                myGraphicsLayer.add(myGraphicLine);

Re: Displaying coordinates on MAP

AshishYadav — Sat, 31 May 2014 09:32:30 GMT

Hi @nasha001,

Thanks for the help again.
I had tried it out the way you have mentioned and as the link says which you suggested.
It did worked when i had the pass the data as static as mentioned in the example.
However, when i retrieve the data from the database and pass it through a loop it marks the point in a randomize manner.
As the result i get a a disturbed polyline on the MAP.
Please find the attachment(i hope i am able to put my concern in front of you again).

Thanks

Re: Displaying coordinates on MAP

AaronNash1 — Mon, 02 Jun 2014 11:54:38 GMT

Have you looked at the API reference? You can use the insertPoint method if you know the order in which the map point needs to go, or you could create an array of mappoints using the addPath method and then create the polyline. Its hard to diagnose an issue without looking at how you are creating the polyline