Global Positioning System Reference
In-Depth Information
3.6.3
Accounting Units of Value
Units of value would normally be money, either credits or debits that are added or
subtracted when the user moves into a zone, along a route, or within an area (often
bounded by what are know as geo-fences). Tolls, entry or exit charges, fare
collection, and movement charges can thus be collected automatically [12]. There
are, however, other units of value that could also be accounted in a similar way to
money, since money is only a form of information in the electronic economy. An
emerging area could be the collection of energy use or pollution emissions to help
manage climate change. Another emerging area could be about collecting units of
personal exercise to help manage obesity, accounting for the calorific value of
steps taken and at what speed and gradient. More futuristic could be the
accounting of virtual gaming credits and scoring for future sporting activities.
The informational processing looks for charging or accounting events and
then follows a set of rules to increment or decrement the user account. Associated
information spaces include user accounts, pricing tables, billing systems, and
scoring systems.
3.6.4
Route Guidance
Time and movement information are combined to provide tracking and movement
prediction based on a dynamic movement model for the subject of the service.
This application is about routing people or objects rather than about routing
information (although the latter can help inform the former). Positional
information need not be continuous but can be inferred provided enough values
are known from spot measurements of position. Routes can be found from maps
and then can be automatically followed. Messages can be delivered to help both
drivers and pedestrians who are following routes and who may need to reroute
based on the contents of the message. Alerts can be generated if deviations are
detected and updates provided if circumstances change. Since routes that are
traveled are only available in certain places, any positions detected that are not on
the route may be indications of new routes.
7
The route guidance system can also
be used to build maps as well as follow them. Time estimates can be calculated
and optimization services included. Geo-fences can be monitored to provide event
information when they are crossed.
Associated information spaces include GIS containing map overlays with
attributes such as post-code data, postal addresses, traffic regulations, traffic
conditions (current, historic, and predicted), legal information relevant to customs,
hazardous loads, areas where offenders may or may not be, and many other
geographical information sources.
7
This is known as simultaneous location and mapping (SLAM) and is discussed in Chapter 9.
