Randomizer For a Polygon (RTS Unity)

Hi, i'm trying to create a randomizer for a polygon. The thing is, because this is not a normal asset, i'm struggling on how to make this work. For example because this uses earth as it's map asset, anytime I want to create something I need a longitude or latitude for the x and y positions.

Ex: OnlineMapsMarkerManager.CreateItem(longitudeAsX, latitudeAsY);

Now I'm trying to create a polygon using this code:

             double lng, lat;
             int n = 0;
             OnlineMapsControlBase.instance.GetCoords(out lng, out lat);
             markerPositions.Add(new Vector2((float)lng, (float)lat));
             if(n == 0)
             {
                 polygon = new OnlineMapsDrawingPoly(markerPositions, polyColor, 1, new Color(1, 1, 1, 
                 0.5f));
                 polygon.n = m;
                 polygonDrawing.Add(polygon);
                 poly = OnlineMapsDrawingElementManager.AddItem(polygon);
                 poly.name = "Polygon";
             }
             n++;
             polygonCenter = new Vector2((float)polygon.center.x, (float)polygon.center.y);

For now I'm using this code to make a randomizer

             for (int i = 0; i < totalObs; i++)
             {
                 foreach(Vector2 child in markerPositions)
                 {
                     x = UnityEngine.Random.Range(polygonCenter.x, child.x);
                     z = UnityEngine.Random.Range(polygonCenter.y, child.y);
                 }
                 OnlineMapsMarker marker = onlineMaps.Create(x, z, texture);
                 marker.scale = 0.2f;
                 marker.n = m;
                 marker.isObstacle = true;
             }

But keep in mind by using this code, sometimes objects will spawn outside of the polygon. I wanted to use a collider for getting the boundaries, but because this asset always redraws any drawings into the mesh, the position of the polygon will always be Vector3(1, 1, 1) whenever it instantiates. Is there any way to workaround it??