Find existing map shapes-Collection of common programming errors

Hi, Can someone help me with regard to best practise for this scenario?  I have base locations that I add to a map via a shape at a specific lat/long co-ordinate.  I then add destination locations the same way;

LatLongWithAltitude

point = new LatLongWithAltitude(latitude, longitude);Shape shape = new Shape(ShapeType.Pushpin, point);The problem I am having is that the base locations can share destination locations and although all the base locations are added to the map, I cannot add the destination locations (there are no runtime errors) and I was wondering if it was because I am trying to add a destination location that already exists on the map.Is it possible to iterate the existing map shapes by their lat/long co-ordinate?

Thanks in advance.