Geoscience Reference
In-Depth Information
pages. This way one would have to store the geographic extends of the
map field in a two-dimensional code that comes with the map like for in-
stance a barcode, QR-Code or Data Matrix. Reading and interpreting of the
code can be implemented by using the integrated camera of mobile devices
and existing software. There are also digital pens that can read barcodes.
The other option would be using unique pattern by printing a different
Anoto pattern on every map. This might seem cumbersome but due to the
total size of the Anoto pattern it is not likely that the pattern will ever be
used up completely. Which solution is to be used depends on the scenario
or business model to be implemented since higher license fees might go
along with the unique pattern model.
Communication between pen and mobile device is carried out via Blue-
tooth. The transfer of data is initiated by the user by pointing the pen at a
special button printed on the paper - a so called pidget. This brings about
certain limitations for the interaction with the system. The device is not
giving any feedback while the user is acting with the pen on the paper. To
solve this one could access the streaming technology by Anoto where a
permanent communication channel between pen and device exists enabling
real-time interaction, however not every digital pen and especially not
every mobile device is capable of this. In the simple case when marking
the pidget the relative coordinates are send to a server where they are
decoded and further processed before sent back to the device where a listen-
ing application will initiate the feedback on the device. In the application
within the NavAD project there are three servers involved in this process.
One acts as an application service handler to interpret the Anoto specific
file format .PGC. This task is performed by the preexisting ActiNote
®
plat-
form developed by project partner Actimage. The decoded pen data is then
sent in form of an XML document to an application server that notices
which request the user demands and processes the coordinates according to
their application. A route request for instance might require a trajectory
optimization since the pen records a lot more points than required for
navigation. The transformation from relative to geographic coordinates
will also take place here. The conditioned coordinates will then be sent to
the listening application on the device via a push web service. This Black-
Berry Push Technology is especially helpful in this scenario as it can trigger
an event on the mobile device from the server side without the device
having to poll for it. When working with BlackBerry the third server, the
BlackBerry Enterprise Server, becomes necessary being a communication
gateway between the device and the rest of the world. The communication
loop is illustrated in detail in
figure 2
.
