Marc Korpus, having had a fascination with maps since youth, took up the creation of of them as an occupation at age 42. He found that mapmaking is now one facet of the discipline of "geographic information systems" (GIS), which marries cartography with databases and statistics and is performed on a computer rather than a drafting board. Until his recent retirement, Marc was a GIS analyst for a nationwide engineering firm, helping engineers and scientists in such endeavors as planning freight railways in New Jersey, monitoring the fish species in New York Bay and routing power from Quebec to New York City.