This large and simple-looking outline map of the waterways surrounding Shanghai is actually the creation of an impressive piece of technology, Thomas Ferguson's 'hodograph'. As described on the map, the hodograph mechanically collected data about the sailing direction and distance of a vessel, essentially allowing for automatic marine surveying. This chart, commissioned by the Imperial Maritime Customs, was one of two attempts by Ferguson to prove the value of his invention to his superiors in Shanghai - the other was a smaller, but extremely detailed map of the canal city of Suzhou.



Locations on the map are marked in English and in Mandarin. The foreign concessions around Shanghai are marked, as are certain buildings important to maritime trade. These include the customs house, the observatory, and a gunpowder factory. The route of a telegraph line from Woosung to Wong Du is also marked. Bridges across the many rivers and canals are drawn according to their passability by river traffic, ranked from 'ample height' to 'too low for any houseboat'.



Ferguson was born on the Dutch island of Aruba, but moved to Shanghai in the late 19th century to work as a surveyor. His inventions, though revolutionary for the period, never quite caught on, but the maps which resulted from them are extraordinary. Alongside his 'hodograph', Ferguson also created a 'cyclograph' for use on a bicycle or automobile, and a 'pedograph' for use on foot.



This map is rare on the open market. Worldcat notes only two institutional examples - one at the British Library and one at the Staatsbibliothek, Berlin.



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