Digital Reference Maps of Capital Prague

The Digital Reference Maps (DRM) are a set of digital maps of Prague that integrates graphical and alpha-numerical data into a comprehensive system. Prague, the capital of the Czech Republic, covers more than 496 square kilometers and consists of 112 cadastral areas and approximately 300,000 parcels, 230,000 buildings, 110,000 addresses, and 36,000 street sections.

The DRM comprise 30 layers that can be combined. The main layers consist of parcels, lines inside parcels, block maps (blocks of land use), addresses, buildings, street sections, and a generalized map. Layers for the cadastral map are kept in two forms--the "real" and the "law"--because of the many ownership changes after 1989. This has created a time lag in updating maps at the Cadastral Authority. In the "real" state, there are objects that best reflect the factual situation although they have not been authorized by the Cadastral Authority.

In addition to the main layers, there are other layers such as orthophotos, several sheet line systems, cadastral and municipal borders, and utilities. Most of the layers of DRM were created in 1993 by scanning and digitizing the 1:1,000-scale cadastral map and the 1:500-scale technical map and joining databases from the Cadastral Authority and the address database.

Since 1995, the maps have been updated from geodetic measurements and aerial orthophotos for better accuracy. The present positional accuracy of more than 80 percent of the objects is better than 14 centimeters. Data is available in ArcInfo coverages and accessible in ArcView shapefiles and some other formats.

The DRM can be used as a base for other GIS applications or for cartographic purposes. There are many users among local government, utility managers, schools, and private companies.