Hubert Frömelt and Michel Guisolan:
The topographical survey of the canton of Thurgau by Johann Jakob Sulzberger, 1830 to 1838
Cartographica Helvetica 17 (1998) 3–17
In 1830, road inspector Johann Jakob Sulzberger (1802–1855) was commissioned to survey the entire canton of Thurgau. This marked the beginning of the official cantonal surveying of Switzerland. Sulzberger decided to use the scale 1:21,600, thus following in the footsteps of his idol Cassini.
The survey results were used for two single sheet maps: 1837 in the scale 1:150,000 as a general map and 1838/1839 in the scale 1:80,000. Both maps were engraved in copper and showed the entire canton as promised in Sulzberger's contract.
On the order of Guillaume Henri Dufour, director of the Topographical Bureau in Geneva, the unusual scale 1:21,600 of the plane table sheets had to be redrawn into the official scale 1:25,000 (originals: Archives of the Federal Office of Topography), which was eventually reduced into the final scale 1:100,000. It is highly interesting to compare the cantonal map 1:80,000 and the topographical map of Switzerland 1:100,000: Both maps were engraved approximately at the same time by the same professional engravers. In the cantonal map, the topographic features are represented with unshaded, so-called 'slope hachures', whereas for the Swiss map, a combination of shaded slope hachures is used. The spot heights, which were measured with a barometer, seem to have posed some problems. Since they are not identical on the two maps or on the plane table sheets, it appears that they had been measured at different times. As customary at that time, heights were measured in feet.
In another set of redrawn plane table series 1:25,000 (State Archives of the canton of Thurgau), the tracks of the future railway line from Zurich to St. Gall are already shown with a red line. Sulzberger's work was widely recognized as a pioneer feat in cantonal surveying.