TY  - JOUR
A1  - Vollmer, Jan Ole
A1  - Trapp, Matthias
A1  - Schumann, Heidrun
A1  - Döllner, Jürgen Roland Friedrich
T1  - Hierarchical spatial aggregation for level-of-detail visualization of 3D thematic data
JF  - ACM transactions on spatial algorithms and systems
N2  - Thematic maps are a common tool to visualize semantic data with a spatial reference. Combining thematic data with a geometric representation of their natural reference frame aids the viewer’s ability in gaining an overview, as well as perceiving patterns with respect to location; however, as the amount of data for visualization continues to increase, problems such as information overload and visual clutter impede perception, requiring data aggregation and level-of-detail visualization techniques. While existing aggregation techniques for thematic data operate in a 2D reference frame (i.e., map), we present two aggregation techniques for 3D spatial and spatiotemporal data mapped onto virtual city models that hierarchically aggregate thematic data in real time during rendering to support on-the-fly and on-demand level-of-detail generation. An object-based technique performs aggregation based on scene-specific objects and their hierarchy to facilitate per-object analysis, while the scene-based technique aggregates data solely based on spatial locations, thus supporting visual analysis of data with arbitrary reference geometry. Both techniques can apply different aggregation functions (mean, minimum, and maximum) for ordinal, interval, and ratio-scaled data and can be easily extended with additional functions. Our implementation utilizes the programmable graphics pipeline and requires suitably encoded data, i.e., textures or vertex attributes. We demonstrate the application of both techniques using real-world datasets, including solar potential analyses and the propagation of pressure waves in a virtual city model.
KW  - Level-of-detail visualization
KW  - spatial aggregation
KW  - real-time rendering
Y1  - 2018
U6  - https://doi.org/10.1145/3234506
SN  - 2374-0353
SN  - 2374-0361
VL  - 4
IS  - 3
PB  - Association for Computing Machinery
CY  - New York
ER  -