Get the map data of a shipment

Use this to draw a shipment's voyage on a map: the sea or air route split into the part already travelled and the part remaining, the carrier's ports, the vessel's upcoming calls, the recorded position trail and the vessel marker. It is the data behind the map on the shipment's page in Trackberry. Long lines are thinned and coordinates rounded to four decimals. When the carrier has published nothing to draw, map has the same shape and draws the shipment's legs between the places its own located tracking events put their ends; it is null only when nothing can be placed. Not paged.