Concepts and Techniques of an Online 3D Atlas – Challenges in Cartographic 3D Geovisualization

Abstract

During the last two decades numerous interactive atlas and mapping systems have been developed, offering a variety of mainly statistical 2d map types like choropleths, point symbols and diagrams but scarcely also some 3d map types like panoramic views and block diagrams. These systems include a bundle of atlas functionality for spatial and temporal navigation, map visualization, and layer handling.

Today, atlas systems have to compete with a multiplicity of freely available map services, geoportals and virtual globes; thus, atlases have to strive for new horizons. At the same time, the big popularity of geodata and geo-applications is offering a unique chance to digital atlas products in order to activate new user groups and to animate them for collaboration.

Results of a detailed survey on current products of geovisualization are pointing out that the majority of up-to-date’s applications is originally dedicated and conceived for web and mobile use. The attractiveness of such applications is primary based on the immediate benefit in everyday life, on the up-to-dateness of the data offered, and on their integrative possibilities. In addition, applications using 3d concepts and virtual globes are persuading users by their intuitive navigation and spatial clarity. However, these applications are rather heterogeneous concerning content handling and cartographic quality.

Therefore, the main challenge for future digital atlases will be to merge the big trends of 3d mapping, online and mobile applications with cartographic design and atlas-specific functionality. Research and development should focus on cartographic 3d visualization and interactivity for different user groups and applications.

The Swiss Atlas Platform (APS) project, launched in 2011, is dealing with these aspects of online 3d cartography in order to set up a basic 3d atlas configuration. Based on this APS, the new product line of Atlas of Switzerland and affiliated atlases will be developed.

During the first project phase, the concept of a 3d atlas platform has been defined, having the potential to realize a unique combination of interactive thematic cartography and 3d atlas technology. From the point of view of system design, the Swiss Atlas Platform consists of extensible modules for spatial navigation, map visualization and information retrieval, unified under a flexible graphical user interface. These modules contain a large number of cartographic and general functions; core functionality will be implemented first which in a later phase can be extended according to user needs.

Currently, work is done on the visualization core module, allowing for 2d and 3d mapping by means of osgEarth – a dedicated virtual globe engine. This visualization engine is capable of handling large amounts of geographical data and web services. Essentially, the system offers 2d and 3d visualization of raster data (DTMs, grids, map sheets, aerial and satellite images) and vector data (choropleths, univariate symbols and diagrams, POIs), and even solid 3d objects. Moreover, it allows for intuitive spatial navigation, layer management, information query, and labeling.

Future core development will be necessary to refine cartographic 3d representation techniques and to implement interactive methods. Concurrently, a flexible GUI for different platforms has to be set up and a lot of cartographic and editorial work has to be done to realize an online 3d atlas application.