Many of the letters in the Stuart State Papers are sent from aboard ships. These are more difficult to represent geographically than regular letter origins. To do so, we gave each such letter two additional pieces of data: the place of sending and a standardised ship name. Through this, it was possible to trace the journey and letters sent from aboard a single ship.
With this information, I developed a method for estimating the shortest-path of a ship’s journey between each intermediary point it visited. This allowed us to find ships with the longest journey, and may be used to find arbitrary points in space where ships may have overlapped.
Further refinements will try to take additional information into account, such as known currents and wind speeds.