topic Re: convert x y to lat long in ArcGIS JavaScript Maps SDK Questions

convert x y to lat long

RichardDeVita — Wed, 29 May 2013 14:12:50 GMT

I have a map with multiple layers. I got this from an example.

streetMap = new esri.layers.ArcGISTiledMapServiceLayer("http://server.arcgisonline.com/ArcGIS/rest/services/World_Street_Map/MapServer", {id:"streetMap"});

map.addLayer(streetMap);

The layers display and I can switch between layers. all is fine.

I can draw on the map. I want to save to points of the polygon. However the points I get from the geometry object are x y not
latitude and longitude.

dojo.connect(tb, "onDrawEnd", addGraphic);

function addGraphic(geometry) {

var pts = geometry.rings;

pts is a array of x and y coords.

How do i get the graphics object to return Latitude and longitude ? Or how do I convert x y to latitude and logitude ?

Thank you

Re: convert x y to lat long

TimDine — Wed, 29 May 2013 16:17:59 GMT

You could project the points using a geometry service.

http://developers.arcgis.com/en/javascript/jssamples/util_project.html

Re: convert x y to lat long

KenBuja — Wed, 29 May 2013 16:56:13 GMT

You can use esri.geometry.xyToLngLat, which translates Web Mercator coordinates to lat/long.

Re: convert x y to lat long

RichardDeVita — Thu, 30 May 2013 14:19:57 GMT

Thank You.

esri.geometry.xyToLngLat is working.

the app is using esri.layers.ArcGISTiledMapServiceLayer to add several layers.

streetMap, imagery, topoolgies and some others

In some variations I also set the extent.

map.setExtent(new esri.geometry.Extent(-144.1358, 7.9814859, -52.76454, 68.8952, new esri.SpatialReference({wkid: 4326})));

Does the wkid have any effect on xyToLngLat ?

Also set layers does not have a wkid parameter. what does it use ?

Again, thank you

Re: convert x y to lat long

KenBuja — Thu, 30 May 2013 16:49:38 GMT

Don't forget to click the check mark and promote the post that best answered your original question.

The conversion will only work for a geographic coordinate system, and I believe (and someone please correct me if I'm wrong) only with 4326.

Re: convert x y to lat long

TimDine — Fri, 31 May 2013 12:15:18 GMT

Correct, that function will only do web mercator to WGS84 Decimal Degrees.

Geometry service sample from ESRI would be used to project between other coordinate systems.

Re: convert x y to lat long

JeffJacobson — Fri, 31 May 2013 21:05:50 GMT

A good alternative to using a Geometry service to do projections is to use proj4js and do the conversions on the client.