The problem of finding the shortest network connection given set of points is often referred to as the Problem of Steiner. The applications of this problem can be found in various engineering fields, typically in the design of telephone networks, in the planning of highway systems or in the design of large mining operations. In the present state of art, for 20 given points or more, one must use a heuristic method to obtain at least a suboptimum solution in a reasonable time.
/lp/association-for-computing-machinery/set-of-test-problems-for-the-minimum-length-connection-networks-uvYJbeM7L7