Why the hinterland is the part nobody else publishes
Maritime data projects usually start with vessels because vessel data is available, and they usually end up unable to answer the question that prompted them.
Vessel movements tell you about ships. Supply chain questions are about cargo, and cargo leaves the port by rail, barge, road or pipe. That onward network is published by the port authority and by essentially nobody else in structured form, which makes this a genuinely non-substitutable source.
The second reason is modal shift, which is an active European policy objective. Moving freight from road to rail and barge is measurable if connections are collected by mode over time, and the port publishes enough to track how the network is changing.
The third is terminal specialism. Not every terminal handles every cargo, and a model that treats a port as one node with one capacity will misroute anything specialised - chemicals, liquid bulk, ro-ro. Terminal level detail is what makes a routing model credible.
The fourth is that a port authority publishes to attract business, which means the data is promotional in tone and generally accurate in substance. We collect the substance and do not treat marketing claims about capacity as measurements.