Usage coordinates

As use coordinates the German and Austrian referred surveying that system of Gauss-Kruger coordinates , the position of all in which for general use surveying - and border points are given.

For practical reasons, the system does not have the highest level of accuracy of the national survey , because otherwise millions of boundary points would have to be changed each time the triangulation or surveying network is revised.

Its status roughly corresponds to that of the 1960s or 1970s, when the underlying first-order network could not yet be calculated in one go , but its adjustment was already mathematically rigorous. Before that, the individual parts (regional blocks or larger operations ) had to be brought together more closely ( fanning ) because the calculation methods or computer capacities were not yet sufficient for extensive networks.

On average, the network of usage coordinates has an accuracy of about 10 ^ -5, which would correspond to 1 cm at a distance of 1 km. However, the neighborhood accuracy can vary where different operations adjoin one another. In the border cadastre of the urban area it is a maximum of a few centimeters, in rural areas and in the mountains sometimes a little more.

In contrast, the first-order network used in science (in Germany the main triangular network ) has a significantly higher accuracy, which can be estimated at about 10 ^ -6 or better. Its points (TP), the average distance of which is 30 km, are determined using the most modern methods and are controlled by satellite geodesy . Slow displacements (millimeters per year) can occur due to regional earth crust movements, but these do not play a role in the utility network. In Europe, the individual national surveys have been merged into international networks of the first order since 1950 ( Europanetz ED50 , ED79 and ETRF ), which increases the accuracy even further.