Geoscience Reference
In-Depth Information
Fig. 1
Mobile 3D mapping architecture
limitations, including limited CPU (Central Processing Unit) and memory, the
absence or limited performance of graphics accelerators, the absence or lim-
ited performance of FPUs (Floating Point Units) and energy consumption issues
(Nadalutti et al.
2006
). When examining any issues related to computing perfor-
mance, it is important to understand the hardware and software architecture of the
system. This understanding leads to the identification of potential bottlenecks in
the rendering process and permits optimisation where possible.
Mobile mapping is generally underpinned by a three-tier architecture (Fig.
1
),
consisting of an end-user device or “client” (which could be a smart phone or tab-
let) a web server (which sends data to the client and retrieves requests from the
client) and a database server, which holds the map and other data to be displayed
(Mitchell
2008
). Based on this architecture, a number of considerations can be
taken into account when rendering data on mobile devices: potential bottlenecks
include retrieving the data from the database, transmitting the data from server to
client over a mobile network (i.e. network bandwidth), and rendering the data on
the device using specialist software that takes advantage of any graphics hardware.
For each of these stages both hardware and software are important. In general, all
through the process, it is important to minimise the amount of data in order to
improve performance.
Initial research carried out in order to overcome limitations of mobile render-
ing focussed on hardware (Nadalutti et al.
2006
). For example (Woo et al.
2001
)
produced small graphic accelerator chips to allow high performance combined
with low power consumption. More recently, many mobile devices have embed-
ded graphics chips, increasingly powerful processing units [and multiple cores
(NVIDIA Corporation
2011
)] and increased memory permitting improved perfor-
mance and drawing them closer to the specification of gaming consoles, although
battery life remains an issue to be solved (Chester
2013
).
Considering the above architecture (Fig.
1
), and defining rendering as the
process of taking data representing the real world (i.e. the 3D City Model) and
