THE GEOGRAPHY OF TRANSPORT SYSTEMS

Source: Ship log data from CLIWOC Project. Data geocoded by
David Hopp.
(Detailed PDF Map)
Officers on board sailing vessels maintained detailed log books of the ships’ activities. These observations, which could be made several times per day, mostly included the ship's position and weather conditions (temperature, wind). Their main purpose was to assist navigation, particularly since its was difficult to accurately estimate the longitude. Since many vessels were engaged in military and commercial activities, such as for trading companies (e.g. English East India Company, Dutch East India Company), a large quantity of ship logs has been kept in national archives. Between 2000 and 2003 a project financed by the European Union, labeled Climatological Database for the World's Oceans 1750-1850, digitized a large sample of log entries, including their location.
The above map plots the density of a large sample of ship logs, which is indicative of the global trade network structure of the 18th century. Due to differences in the number of log entries geocoded, such as only 7,698 entries for French flagged ships as opposed to 83,036 entries for UK flagged ships, there are density variations that are not necessarily reflective of the size of nationally flagged fleets and their level of commercial activity. Limited shipping is observed over the Pacific Ocean, mostly due to the yet limited scale of European involvement in this part of the world at that time. The second half of the 19th century will show an intensification of maritime trade to and across the Pacific with the First Opium War of 1838-42 being the turning point. Prior, the China trade was mostly serviced by Portuguese flagged ships, which are not covered by the sample.
The following observations can be made regarding the respective trade patterns of national flagged ships for the 1750 to 1810 period: