LOD 1 VS. LOD 2 – PRELIMINARY INVESTIGATIONS INTO DIFFERENCES IN MOBILE RENDERING PERFORMANCE
The increasing availability, size and detail of 3D City Model datasets has led to a challenge when rendering such data on mobile devices. Understanding the limitations to the usability of such models on these devices is particularly important given the broadening range of applications – su...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2013-09-01
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| Series: | ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences |
| Online Access: | http://www.isprs-ann-photogramm-remote-sens-spatial-inf-sci.net/II-2-W1/129/2013/isprsannals-II-2-W1-129-2013.pdf |
| Summary: | The increasing availability, size and detail of 3D City Model datasets has led to a challenge when rendering such data on mobile
devices. Understanding the limitations to the usability of such models on these devices is particularly important given the broadening
range of applications – such as pollution or noise modelling, tourism, planning, solar potential – for which these datasets and resulting
visualisations can be utilized. Much 3D City Model data is created by extrusion of 2D topographic datasets, resulting in what is known
as Level of Detail (LoD) 1 buildings – with flat roofs. However, in the UK the National Mapping Agency (the Ordnance Survey, OS) is
now releasing test datasets to Level of Detail (LoD) 2 – i.e. including roof structures. These datasets are designed to integrate with the
LoD 1 datasets provided by the OS, and provide additional detail in particular on larger buildings and in town centres. The availability
of such integrated datasets at two different Levels of Detail permits investigation into the impact of the additional roof structures (and
hence the display of a more realistic 3D City Model) on rendering performance on a mobile device. This paper describes preliminary
work carried out to investigate this issue, for the test area of the city of Sheffield (in the UK Midlands). The data is stored in a 3D
spatial database as triangles and then extracted and served as a web-based data stream which is queried by an App developed on the
mobile device (using the Android environment, Java and OpenGL for graphics). Initial tests have been carried out on two dataset sizes,
for the city centre and a larger area, rendering the data onto a tablet to compare results. Results of 52 seconds for rendering LoD 1 data,
and 72 seconds for LoD 1 mixed with LoD 2 data, show that the impact of LoD 2 is significant. |
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| ISSN: | 2194-9042 2194-9050 |