public override void OnInspectorGUI()
    {
        base.OnInspectorGUI();
        MapGraphics mg = (MapGraphics)target;

        if (GUILayout.Button("Generate"))
        {
            while (mg.transform.childCount != 0)
            {
                GameObject.DestroyImmediate(mg.transform.GetChild(0).gameObject);
            }
            mg.BuildMap();
        }
    }