To accomplish its tasks the Federal administration has collected a large quantity of space-referenced data. To use these data stocks appropriately in geoinformation systems it is necessary to integrate the data from different sources. The development of procedures for the integration of geodata serves this objective.
These procedures include as core elements techniques serving the assignment of elements representing in each case the same object or object part in the landscape, but which are differently represented in the single datasets. Depending on the relevant task these procedures for data integration are based on geometry, topology, semantics, or a combination of these themes.
BKG faces a high priority application of procedures for geodata integration in the case of the use of address data with the ATKIS® basic DLM. Up to now address data are not yet provided by all Länder (states of the Federal Republic) in the basic DLM. BKG has developed a semiautomatic procedure as compensation for the data still lacking of the Länder, which integrates address data into the basic DLM. The dataset covering the whole territory of the Federal Republic of Germany originates from a supplier who has acquired this punctiform information in a form appropriately matching with the geometry of the road axes of a provider for vehicle navigation systems. These data do not fit both geometrically and topologically into the frame of the required geometric accuracy of the basic DLM.
The procedure developed at BKG for the integration of the datasets determines and compares in a first step the roads of the basic DLM with those contained in the navigational data and performs an assignment taking into account the geometry and topology. On completion of the assignment this procedure computes the displacement vectors and applies these vectors also to the point coordinates of the addresses. Subsequently, an operator verifies the addresses that have been transformed into the basic DLM through a semiautomatic process visually on the screen.
Hydrographic feature codes
A second main field of application concerning procedures for geodata integration consists in the editing of ATKIS® data stocks for the purpose of auditing within the scope of the Water Framework Directive (WFD) of the European Union.
This audit is done by means of geoinformation systems and requires attributing of the data in the DLM with the official hydrographic feature codes. This attributization has already been executed manually. The DLM250, too, necessitates appropriate editing.
To minimize the amount of work procedures were developed through which the hydrographic feature codes are transferred, in an automation-assisted manner, from the DLM1000 into the DLM250. For this purpose, first an assignment of the water elements between the two resolution levels is performed on the basis of geometric and topological characteristics. The hydrographic feature code is transferred from the DLM1000 into the DLM250 and at the same time a plausibility check performed while taking into account further attributes. The plausibility parameters support the operator with the final interactive control.