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R. Rössler:
"Rendering Interactive Maps on Mobile Devices Using Graphics Hardware";
Supervisor: M. Wimmer; Institut für Computergraphik und Algorithmen, 2012.

Mapping and navigation applications on mobile devices such as smart phones or tablets are increasingly popular. Modern maps are often rendered directly from vector data. Since the performance of a previous CPU-based map renderer was unsatisfactory, a hardware accelerated map rendering prototype for mobile devices based on OpenGL ES 2.0 was created. A novel hybrid rendering architecture is introduced to combine the advantages of tile-based and true real time rendering solutions. The architecture consists of a tile server that renders base map tile images and a client to display them. The new third component, the post-processor, draws dynamic map features such as icons and text above the tiles in real time, enabling a 3D fly-over mode. All components run inside the same process directly on the device. For the rendering of lines, an important map feature, a new rending algorithm was developed, enabling to draw lines of arbitrary width with one of three different line cap styles. Additionally the line can be stippled with a user-defined pattern where each line dash is rendered with the selected cap style. Antialiasing of the line is supported with an arbitrary circularly symmetric filter kernel of userdefinable radius. To accelerate icon rendering, a texture atlas is used to store the icons, and a simple but effective packing algorithm has been developed to generate the atlas online.

http://publik.tuwien.ac.at/files/PubDat_211912.pdf