topic Re: Create polygon without sketching in ArcGIS Pro SDK Questions

Create polygon without sketching

AndrewAlexander1 — Mon, 14 Nov 2022 23:45:15 GMT

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

Re: Create polygon without sketching

FridjofSchmidt — Tue, 15 Nov 2022 08:39:08 GMT

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.

Re: Create polygon without sketching

NarelleChedzey — Tue, 15 Nov 2022 08:39:33 GMT

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