Ground point (geodesy)

In surveying, a ground point is a measurement or fixed point whose upper edge is at ground level or just a few centimeters above it. The term has entered technical practice in order to distinguish such damage- safe marketed points from others, such as church towers or tower bolts , triangulation pillars or TP stones, pole signals , fork or measuring points attached to buildings or the mostly 10–30 cm high boundary stones .

A ground point can be marketed in several ways:

• in the mountains as a rock mark (carved cross),
• in shallower areas as ground-level buried surveying or KT stone (as it was called in former Austria-Hungary),
• in city surveying and in construction projects as screw bolts ,
• as a metal pin or nail (usually with the inscription "measurement point" or a red colored ring),
• or simply with a firmly driven wooden stake when setting out .

The main advantage of ground points is better protection against erosion and other damage, but one disadvantage is that they often become overgrown quickly, making them more difficult to find and can require digging. In such cases, a point description with a sketch of the location and exact blocking dimensions is helpful for quick and reliable identification .

The measurement of such ground points is usually carried out with the theodolite (angle and distance measurement ) relative to other fixed points, but also with differential GPS , and with low demands with alignment or a tape measure .