M. Lechthaler

Vienna University of Technology



A national atlas information system NAIS is the cartographical calling card of a country. Because of the new potential of the global net, web national atlases are becoming more and more important for national geo-data policy and society. The concepts for multimedia national atlases point at the new meaning of the web atlas map as an interactive interface, through which one can reach the current elementary geo-data portal. The maps convey topographic as well as thematic information based on a consistent succession of map scales. 

This paper discusses research results developed during the realisation of the prototype of Austria Atlas Information System ÖROK Atlas Online. The map graphics pose as an essential part of the graphical user interface that enables the user to investigate the provided geo-data. It will focus on technical restrictions of the screen as an output medium and the principles of scale-adapted cartographic data preparation on one hand.

On the other hand, it is important to limit the range of possible interactions to reasonable functionalities. This was done without making the user feel restricted. Therefore this form of navigation is called "restrictive-flexible".

Using legible map graphics in NAIS which are adapted to the technical requirements of the output medium is one of the main criteria for user acceptance. Today, the NAIS has to present a hybrid system which allows a cross-media publishing.  A hybrid system is relying on cartographically improved map graphics suitable for both screen visualisation and high-quality printing. Map graphics for the screen and printing medium differ in visualisation depending on the output medium resolution. By establishing connections between the two media, a method for the production of adequate paper maps in a high graphical quality as an integral part of the system was smoothed.

As an example, the usability of related map graphics for 1:250k screen visualizations and 1:1mio printing will be shown.

By designing the NAIS, the system designers also take responsibility for restrictions in terms of what is not accessible or useful. So the user cannot get any model by his interaction with the system. This would soon lead to useless and illegible visualizations of topographic as well as thematic data. Thus, restrictive-flexible system logic is considered by the editorship.

Therefore, the once passive user of a map becomes an active manager in geographic information acquisition and visualization. The role of cartographers as designers of the NAIS has also changed. They become responsible not only for transport of cartographic legible screen information via Internet, but also for all applied technological functions which allow the user to communicate online with the system.