Add polygon to DTO convert strategy

StructureHelperCommon/Models/Shapes/IPolygonArcSegment.cs

@@ -0,0 +1,31 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace StructureHelperCommon.Models.Shapes
+{
+    /// <summary>
+    /// Implements arc segment of polygon
+    /// </summary>
+    public interface IPolygonArcSegment : IPolygonSegment
+    {
+        /// <summary>
+        /// Vertex of center of arc
+        /// </summary>
+        IVertex Center { get; }
+        /// <summary>
+        /// Radius of arc segment, meters
+        /// </summary>
+        double Radius { get; }
+        /// <summary>
+        /// Start angle, Radians
+        /// </summary>
+        double StartAngle { get; }
+        /// <summary>
+        /// Sweep angle, Radians
+        /// </summary>
+        double SweepAngle { get; }
+    }
+}