Sighting device for surveying with theodolite - comprises centimetre rule graduated about central zero and slidably mounted on element attached to ground stake

摘要

The device is used to directly read ground profile heights by a row of stakes (9,10). Included is a graduated slide (1), on which the zero graduation is in the middle of the slide with centimeter graduations on both sides of the zero. The slide (1) is mounted on a surveyor's rod (8) so that the zero graduation is situated on the sighting line (13) which is parallel to the line (12) of the projected work. To read the heights, the theodolite (14) height above the line (12) of the projected work is calculated and the surveyor's rod (8) on the furthest stake (11) is sighted. The difference between the ground level and the line (12) of the projected work is calculated. The slide is positioned on the surveyor's rod (8) of the furthest stake (11), and a row of stakes (9,10) is placed then directly read.