DAT-based Geographical Information System of Debrecen

Relevant background information: At the end of the 90s the National Cadastral Programme was established in order to create the digital base map of Hungary for the property register offices and the local governments. This project is also supposed to create an infrastructure which makes possible for the land registry offices to register any change in ownership much faster and more accurately than before. In 1997 a standard was established for the digital base maps (DAT standard, MSZ 772-1:1997) which determine the creation and management processes as well as the format of these maps.

• Antecendents
  
  Due to its participation in the National Cadastral Programme, the Mayor’s office of Debrecen has received the digital base map of the town in DAT data-exchange format and the digital orthophotos with a resolution of 20 cm, which belongs to the digital base map. A geographical informational system was required which could manage this dataset immediately and efficiently. It was also a requirement that the system could be adapted to future needs. Owing to its suitability for this application, the ErdaGis system by Erda Kft was chosen.
• The mission and strategical aim of the project
  
  To create a base geographical information system which is modular enough to serve as a basis for the creation of specialised systems such as open space registry, property management system for the local government, etc. in the future.
• Applied methods, results achieved by the contributors
  
  The GIS system was established using ErdaGis system. The digital base map provided in the DAT data-exchange format was loaded into separate projects by districts with the DAT-loader module of ErdaGis. It is possible to display and query data in DAT exchange format with this ErdaGis module. The user is not allowed to edit neither descriptive nor graphical data. The system can load whole DAT files which do not contain deleted elements. The load operation deletes all previously stored data, and only the data of the loaded file will be visible for the user. This is particularly important, because the dataset will be updated with DAT-based digital maps provided by the land registry office. The property registry data required for the update is provided by the land registry office as well.
  
  Orthophotos – which use 9 GB of disk space – are managed on two levels. Photos with resolution of 20 cm are displayed if display resolution is greater than M=1:4000. If resolution is less than M=1:4000 then photos with resolution of 1 m is used.
• Improvements
  
  The current implementation manages districts as independent projects. These projects should be merged into one project using ErdaGis 2.0. Another issue is to integrate the settlement management plan into the system. The latter is performed by VÁTI KHT with ARC/INFO software package. A converter module is under development for ErdaGis, which could read data generated by ARC/INFO and is able to make queries such as retrieving plan directions, thematic plans based on topographical numbers, and is capable to display customized regularization plans. To print data, a template should be created, which contains the plan specifications for the plot, the actual part of the regularization plan and its key, and an overview of the area, which contains the block as a point. These improvements can be worked out during the autumn of 2001. Further developments could be made with creating the open space registry system and the property registry system for the local government.
  
  
• Organizations:
  
  Debreceni Városi Informatikai Központ Kft.
  
  Erda Kft.