Projecting polygon using ArcGIS API for JavaScript?

Question

I have polygon data as:

POLYGON ((1645481.0939999996 6124506.9885, 1645470.0473999996 6124473.5406, 1645475.7094 6124440.1391,1645481.0939999996 6124506.9885))

in wkid=2193

I want to project this polygon using geometry service with new spatial reference wkid= 3857.

I was able to project point using similar data on new spatial reference wkid=3857, but that is not happening with polygon.

Which method should I use to project polygon using geometry service?

 function addGraphic() {
 var wkt = new Wkt.Wkt(); 
 wkt.read("POLYGON ((1645481.0939999996 6124506.9885, 1645470.0473999996 6124473.5406, 1645475.7094 6124440.1391,1645481.0939999996 6124506.9885))");
 var polygon = wkt.toObject();
 //set the spatialreference
 polygon.SpatialReference = new esri.SpatialReference({wkid: 2193});
 var outSR = new esri.SpatialReference({ wkid: 3857 });
 var gsvc = new esri.tasks.GeometryService("http://tasks.arcgisonline.com/ArcGIS/rest/services/Geometry/GeometryServer");
 var projPoly;
 gsvc.project([polygon], outSR, function (outGeom) {
 projPoly = outGeom[0];
 var symbol = new esri.symbol.SimpleFillSymbol().setStyle(esri.symbol.SimpleFillSymbol.STYLE_SOLID);
 var polygonGraphic = new esri.Graphic(projPoly, symbol);
 map.graphics.add(polygonGraphic);
 });
 }

• Ashish: user esri.symbol.SimpleFillSymbol.STYLE_NULL

Answer 1

There are two issues that you need to solve.

• Firstly, the polygon that you have, is in a format that is called the WKT. You will have to convert it to a geometry in the ESRI's JavaScript format. I have used Wicket in the past to do this conversation for me.
• Once you have an ESRI Polygon, you can use the project operator on the GeometryService. You should make sure that you set the spatialreference on the polygon, before you send it to the service.

You can use code similar to this:

 function projectToWebMercator() {
 var wkt = new Wkt.Wkt();
 wkt.read("POLYGON ((1645481.0939999996 6124506.9885, 1645470.0473999996 6124473.5406, 1645475.7094 6124440.1391,1645481.0939999996 6124506.9885))");
 var polygon = wkt.toObject();
 //set the spatialreference
 polygon.setSpatialReference(new SpatialReference({
 wkid : 2193
 }));
 var outSR = new SpatialReference({
 wkid : 102100
 });
 var gsvc = new GeometryService("http://tasks.arcgisonline.com/ArcGIS/rest/services/Geometry/GeometryServer");
 gsvc.project([polygon], outSR, function (outGeom) {
 console.dir(outGeom); //<-- Do whatever you want with the projected Polygon here
 });
 }

• Dips: I've tried to convert WKT to a geometry using arthur-e.github.io/Wicket/sandbox-arcgis.html, but its not showing up anything. Can you please send me some sampple code? I had similar coordinates for point, but when I project them using new spatial reference and geometry service, it worked. Please guide me.
• Devdatta Tengshe: @Dips: I've added the code. Don't forget to add the two scripts from Wicket in you HTML file.
• Dips: hey..Thanks for the code, but still not getting those two scripts to add from Wicket, please guide me.
• Devdatta Tengshe: What do you mean when you say 'not getting those scripts' did you download those scripts from github?
• Dips: I've added scripts and modified code as per your directions, but still its not showing up polygon on the map. Please check my above edited code. If I modify polygon data i.e. add more coordinates to it around 40 coordinates, it doesn't call gsvc.project method.