There are several ways to climb the Katzenstein from the Schwarzwassertal. However, you also have the option of driving via Pobershau to the hiking car park at Katzenstein and then walking a few meters.
"The Royal Saxon Triangulation (here with the historical proper name) is a land survey carried out in the years 1862 to 1890 on the territory of the Kingdom of Saxony with simultaneous creation of a trigonometric network." - de.wikipedia.org/wiki/K%C3%B6nlicher-S%C3%A4chsische_Triangulirung