Joseph Liesganig

Joseph Xaver Liesganig (13 February 1719 – 4 March 1799) was a Jesuit priest and geodesist who was a professor of mathematics at the University of Vienna.

He was involved in measuring the extent of Austria, establishing the longitude of Vienna and in early trigonometrical mapping of the region.

Other collaborators included Karl Scherffer (1716-1783), Georg Ignaz von Metzburg (1735-1798) His Vienna triangulation was re-examined in 1806 and it was found to be in error only by about 7mm per kilometre.

[3][4] In 1772, parts of the Russian Empire went into Austria and Liesganig was ordered to map the new territory of Galicia and Lodomeria (Volyhnia).

He was assisted by Franz Xavier von Zach (1754–1832) and he moved his instruments from Vienna to the observatory at Lviv where he then worked until his death.