Braak Base Line
The Braak Base Line was the baseline for the state survey of the Duchy of Holstein, the Danish state, the city of Hamburg and the Kingdom of Hanover (Gaussian state survey). Its length was measured in 1820/21 by Heinrich Christian Schumacher between the two trigonometric points near Braak in the district of today's Brunsbek in the district of Langelohe and Ahrensburg. After the reduction by Christian August Friedrich Peters in 1853, the length was determined to be 3,014.45115 toises (5,875.2747 meters).