topic Re: Saving points while drawing a polygon in ArcGIS JavaScript Maps SDK Questions

Saving points while drawing a polygon

RichardDeVita — Tue, 23 Apr 2013 18:16:11 GMT

I downloaded the sample cod: Add graphics to a map
http://help.arcgis.com/en/webapi/javascript/arcgis/jssamples/graphics_add.html

I want to save the points (lat and lon) of a polygon as its being drawn or at "ondrawend" and get a list of all the points.
Not a free style line drawing, just a straight line polygon.

In the function addGraphic (geometry) is there a way to do this

var points[] = geometry.getPoints();

I need to save the points to a jsonstore.

Thank You

Re: Saving points while drawing a polygon

JakeSkinner — Sat, 11 Dec 2021 19:52:39 GMT

Hi Richard,

You could use the onDrawComplete event to do this. Ex:

dojo.connect(tb, "onDrawComplete", function(geometry){
            console.log(geometry.geometry.rings);
            });

Re: Saving points while drawing a polygon

RichardDeVita — Tue, 23 Apr 2013 19:24:56 GMT

Thank You. This is a start.

ran this
console.log(geometry.rings);

got this
[[[-13459684.212552793, 4676535.610062524], [-13453282.61143392, 4673535.456702335], [-13459588.666267438, 4670917.488483570], 2 more...]

how do I convert these numbers to latitude and longitude ?

Also I drew a triangle, but I get 5 points ?

Thank You for the help

Re: Saving points while drawing a polygon

JakeSkinner — Wed, 24 Apr 2013 09:39:57 GMT

If your map's spatial reference is Web Mercator or Geographic, you can use the geographicGeometry property of the onDrawComplete event. This will return the XY coordinates in lat/long.

console.log(geometry.geographicGeometry.rings);

When creating a triangle you should get 4 points. The 4th point will be a duplicate of the first point. When you digitizing, double-click the 3rd point and the triangle will auto-complete. If you are trying to close the triangle yourself by double-clicking on the 4th point, it will create a 5th point unless you are exactly clicking on the starting point.