Create polygon without sketching

[AndrewAlexander1]

Hello,

Another simple question, I'm sure.  I'm wanting to draw a polygon on the map programmatically.  I don't want to sketch with the mouse.

I see the code for making the polygon, but all the examples I've found have the geometry input from sketching.  But I don't have that geometry.  What does the geometry look like that I can send to the polygon?  I've tried all kinds of ways but so far haven't gotten it.

Ultimately, I want to have text and other objects inside the polygon.

Thanks
Andy

[FridjofSchmidt · Accepted solution]

You can use PolygonBuilderEx.CreatePolygon() to create polygons from 2D or 3D coordinates, MapPoints, Segments, Multipoints, Envelopes or other Polygons, with or without Spatial Reference.

[NarelleChedzey · Accepted solution]

Hi Andy, 

Here's a short example of how to create a polygon.  

// current exent of mapView
var extent = MapView.Active.Extent;

var height = extent.Height;
var width = extent.Width;
var centerPt = extent.Center;

// new xmin, xmax, ymin, ymax values - a subset of the extent
var xmin = centerPt.X - width / 4;
var xmax = centerPt.X + width / 4;
var ymin = centerPt.Y - height / 4;
var ymax = centerPt.Y + height / 4;

// create 4 corners of the new polgyon
var pt1 = MapPointBuilderEx.CreateMapPoint(xmin, ymin, MapView.Active.Map.SpatialReference);
var pt2 = MapPointBuilderEx.CreateMapPoint(xmin, ymax, MapView.Active.Map.SpatialReference);
var pt3 = MapPointBuilderEx.CreateMapPoint(xmax, ymax, MapView.Active.Map.SpatialReference);
var pt4 = MapPointBuilderEx.CreateMapPoint(xmax, ymin, MapView.Active.Map.SpatialReference);

// then create a polygon from the set of points
var listPoints = new List<MapPoint>() { pt1, pt2, pt3, pt4 }; 
var polygon2 = PolygonBuilderEx.CreatePolygon(listPoints, MapView.Active.Map.SpatialReference);

There's also the following documentation that can help you discover more about building geometries.   - https://github.com/esri/arcgis-pro-sdk/wiki/ProConcepts-Geometry

There are a lot of different code snippets here too. - https://github.com/esri/arcgis-pro-sdk/wiki/ProSnippets-Geometry

Thanks

Narelle