Geography Reference
In-Depth Information
investigates the possibility of combining mobile phone and RFID tags. The mobile
phone senses the RFID tag and can download or add new information unique to
that location (Garner et al.
2006
; Coulton et al.
2006
).
An application called ''Mobispray'' uses the cell phones' orientation sensor and
a projector to virtually draw on objects (Scheible and Ojala
2009
). The mobile
device is in essence a virtual spray can.
Another example related to our own system is MapChat (Chimienti et al.
2010
).
MapChat is a collaborative social system that takes advantage of the spatio-tem-
poral aspects of any planning or discussion. MapChat supports various modes of
participatory input into spatial decision support.
5 General Architecture
5.1 The Basic Architecture
There are a number of location services that can more or less accurately pinpoint
the absolute positioning of the device. The Android OS offers the ability to use any
of the existing LBS systems as the location source, so it makes it easy to use
whatever is available. It can be a built-in GPS receiver, or an external GPS unit
connected via Bluetooth. If a GPS fix cannot be found, most telecommunication
operators offer a location service that is based on triangulation of the GSM
(Groupe Spécial Mobile) transmit/receive towers. Another less accurate method
would be to use the unique identifiers of the nearby WiFi hotspots, and estimate
the location using this method.
Once the device has its position information determined and is satisfied that the
error is small enough it will display the location over the application presentation
layer, which is the Google Maps view in our case. Using the location information
the map is centered on the device's current location.
After the location information has been obtained, the application needs to
establish contact with the Virtual Sticky application server. This can be done via
GPRS, 3G, WiFi or any other means to connect to the Internet with a mobile
phone. This connection is vital, because all the virtual information about the
device's surroundings is stored on the server (Fig.
2
).
All requests for data are handled by the server and sent back to the client
(mobile device). To lessen the computational load on the phone and to decrease the
amount of data sent between the server and phone, the server handles the distance
calculations to figure out which data objects are close enough to the device or in
the user specified radius to be included in the data transmission.
