I think this thread has been confused from the outset by us discussing different definitions of "shipping".
My interpretation of the OP was its concern with "shipping"; sending goods by a parcel/freight service using road, rail, air, sea or whatever, (eg DHL, FedEx). This is typical going to be from consignor to hub, to hub, to consignee. In this context, shipping (parcel service) is going to depend to some extent on geography, but geographical priorities will be way below the commercial-drivers of politics, population density, location of financial hubs, value of the goods, urgency and differing customs/tax regimes. This is unlikely to infer much about the shape of things.
On the other hand, some people have interpreted it as "shipping"; big boats sailing across oceans between seaports, eg Exxon, MSC, Maersk. The decisions about which ports to use are going to be driven by the same commercial-drivers as shipping (parcel service), but once the goods are on a big boat it is just going to take the fastest, safest route from port to port. These routes are going to say quite a lot about distances, and infer a lot about the shape of the Earth.