I am trying to replicate a GIS exercise that Donaldson& Hornbeck (2016) did for their paper “RAILROADS AND AMERICAN ECONOMIC GROWTH: A ‘MARKET ACCESS’ APPROACH”. As a part of data construction, they created multiple point-to-point connections on water bodies what allows all possible routes. These routes can only originate from certain points/harbors on land.
Additional notes from the paper:
Their data description is: “Multiple point-to-point connections throughout the Great Lakes and Oceans”. On data creation, they just mention that they “Created manually to effectively saturate area”.
In the main text they explain this as following: “For lakes and oceans, we saturate their area with ‘‘rivers’’ that allow for a large number of possible routes.”
And as a footnote this text, they have: “We do not permit direct access to lakes and oceans at all points along the coast; rather, we restrict access to ‘‘harbors’’ where the coast intersects interior waterways.“