Global Positioning - Programming GPS and OpenStreetMap Applications with Java - page 33

Part II
Global Positioning
Now that the vision has been thoroughly discussed and analyzed, it is time
to begin the mission. The vision was split into three main components RO
(client), ROApp (server), and ROAF. Before tackling the implementation
of these components, this part will provide the prerequisites to synchronize
real-world data in space and time.
Physical laws of motion are generally described in isolated values,
beginning at the (x;y;z)-coordinate (0; 0; 0) and moving along the x-axis.
These laboratory coordinates neglect the relative where and when. In order
to relate real-world activities, every event has to be translated into a global
coordinate system and absolute time. Motion has to be transformed from
spatial coordinates to metric units to reflect, for example, the speed of a
car on a map. GPS coordinates and projection systems will be discussed in
order to build a virtual GPS unit as the heart of the ROAF to synchronize
object motion in space and time.
The three main components of the ROAF do not specify a visualization
frontend. There are simply too many commercial and free (map) tools
on the market for drawing with spatial coordinates. Nevertheless, a very
simple MapPanel will be developed to visualize positions and routes for
ROAF development. This process will also be used to point out the idea of
a framework by looking at the architecture of the Java Swing Framework
with the platonic Component . This excursion should help to clarify the vision
of the ROApp framework with its platonic RealObject .
At the end of this part, the components for global positioning, time
keeping, and drawing of spatial data is combined in a GPX viewer. GPX
is the most commonly used (exchange) format for GPS data. This tool,
with its subcomponents, should come in handy for every ROAF developer
to analyze spatial data, which is available on the internet.