Verification of mathematical boundary carried along the center of riverbed

Abstract

Bringing the data contained in the National Geodetic and Cartographic Resources (PZGiK) to the form required by the present provisions of law is a costly and long lasting process, but it must be carried out. In the effect, not only the form of PZGiK documentation will be changed into a digital one, but the data will be updated.
The PZGiK databases concern i.a. topographic objects, real estate cadastre and the National Register of Boundaries. The objects contained in these datasets should be related to each other. It would be most difficult to find geometric links between elements which by their nature vary in time. They would primarily include flowing surface waters and their direct surroundings affected by these waters.
The configuration of contours of lands and even registered boundaries in cadastral databases should result from the shape of riverbed and its representation in topographic databases. In turn, these boundaries influence the National Register of Boundaries. The boundaries of the territorial division of the country defined along rivers may run in the middle of rivers. Updating of these boundaries should be based on shorelines determined and entered to land registers and topographic objects databases.
The aim of this paper is to present a method of determination of the middle of the riverbed based on measurement of the shorelines and to verify how the use of the algorithm presented will influence the shape of administrative boundaries defined along rivers.