Mobile mapping: challenges and limitations

Mobile mapping: challenges and limitations

U. Srinivas¹, S. M. C. Chagla², Dr. V. N. Sharma³
InfoTech Enterprises Limited, Plot # 11, Software Unit Layout
Infocity, Madhapur, Hyderabad – 500 035
srini@infotech.stph.net¹, chagla@infotech.stph.net², sharma_vempaty@infotech.stph.net³

Convergence of Internet and Media like Voice and video are opening lot of services to the Mobile user. Mobile mapping is the latest and probably one of the most useful of these services. It has myriad uses and plays a pivotal role in the GIS-information dissipating systems. WAP and other wireless standards enable multidimensional access to the map information and are in the forefront of latest mobile mapping technology . The information is made available on mobile devices like WAP Phones, PDAs, Pagers and even ordinary telephones.

Mobile Mapping Infrastructure and architecture
There are different terminals by which the GIS information can be accessed. They are namely Wireless Phones, PDA’s and Land Phones. The principle behind the transmission of GIS content to various terminals is briefed below.

Fig. 1: Access of GIS information on Monile Terminals

Wireless Phones
There are different types of Wireless phones like WAP, GPRS, Imode, PDA’s. They differ in the Wireless Network they use and each of them may have a different methodology to access Map-Information as briefly described below.

WAP Phones
For WAP based mapping solutions, a web server is required that hosts the Mapping Application, has the map database, other components for routing/voice recognition etc (Fig.1). A WAP Gateway is required to transfer information between the Mobile terminal and the web/content server. The Gateway essentially does the protocol conversion, encoding and decoding. A WML browser on the WAP device displays Map and other text based results (Routing results etc).

GPRS Phones
If the GPRS device user is requesting for HTML based map information then the architecture as shown in Fig. 2 will be followed, if the user is requesting WAP based map information than the architecture will be as shown in Fig.1. The only difference being that the wireless network is a Packet switched data network instead of Circuit switched data network, which needs a dial-up.

Fig. 2: Accessing Map content on devices that can connect to the Internet

IMode Phones
The Map services can be delivered to I-Mode phones in more or less similar ways to the WAP model discussed earlier (Fig. 1). The difference being that IMode uses CHTML instead of WML. CHTML is a subset of HTML. Imode is implemented with a packet switched system, which is in principle always on while WAP systems in Europe are at present circuit-switched, i.e. dial-up. Packet switching or circuit switching has a technical difference in the telecommunication system on which the services are based; it has nothing to do in principle with the IMode and WAP standards by itself. In principle, IMode and WAP encoded WebPages can be delivered over packet and circuit switched systems.

PDAs
If the PDAs have a WAP browser installed in them, the information comes in similar fashion as discussed under Wireless phones section above. Some PDAs (Mostly WindowsCE based devices) can access Internet content directly. (Fig 2.) Alternatively, applications running on the PDAs can directly connect to remote servers, retrieve and display information without depending on any browser to display the information. The application running on the PDAs should themselves have interfaces to display the information.

PalmOS Devices
For PDAs like PalmVII – which can’t access Web content (HTML) directly then Web Clipping comes into picture. In such devices PQA (Palm Query Applications) have to be developed on the Palm devices that clip the web-content and receive the bare minimum to display the Map information.

WindowsCE devices
They can connect to the Internet directly as they have in-built soft modems. Thus these devices can directly access Map content from the server, as desktop computers would do.

EPOC devices
These devices can connect to the Internet directly to access Map information. EPOC devices having WAP browsers can have access to the WAP versions of the Map content (Fig. 1). There are other mobile devices like Linux and Embedded Linux devices, Neutrino devices etc. Most of these can connect to the Internet through soft/hard modem and access GIS information.

Land Phones
Having access to information from the Internet without actually connecting to the Internet – One of the ways this is possible is by IVR -Interactive voice response (Ma, 1987). The user who subscribes to the voice service will need to dial a toll free number to get map related information. Software on the server understands the speech and converts that to a text based request to the application server (In our case the map application). Since this facility is available for subscriber only- the voice recognition and demographic recognition software can understand the speech of the user.

Mobile Mapping applications
The mobile applications could deliver the Map Information in different ways such as a) Text: Address and phone of nearest bank, driving direction, Job dispatch operations based on user’s location. b) Image: The path to the service location, on a map. c) Voice: Driving directions, Job dispatch operations. d) Video: Fly-By movies, Traffic congestion Status. There are multifarious applications for Mobile mapping of which the most prominent applications are described below.

Routing applications
Routing could be one of the most popular GIS based solution on mobile terminals. The mobile user could indicate his origin, destination and via locations to the mapping system. Some inputs can also be taken from the GPS device directly. With good transmission speeds (GPRS and higher), the mobile user can also have route guidance (If GPS device is used along with the mobile terminal) on the move. The mobile terminal would get the route result from the server in the form of a detailed way-description- the way description itself can be a text-based display or a voice based directions. The route can be highlighted on the map and shown on the Mobile Terminal. Routing applications can result in the following data being delivered to the Mobile terminal.

Search facility applications
Such location-based applications could search the map database for locations queried according to the preferences given by the user. The user could request information regarding any facility like Hotels, Banks etc around any given location within certain radius. The user’s location itself can be taken from the GPS device if it is attached to the mobile terminal.

Job dispatch and Fleet management applications
This is more of a messaging solution that works with a GPS device or a Mobile positioning system . The field workers, sales people, trucks can be located on a map. The system can track them, send them jobs, receive job progress and job completed forms.

Live Traffic reports
Wireless cameras can be placed at important road crossings that record and transmit the live traffic images to a web-server. This way the user on the move can plan to take an alternative route, if required, to his destination by looking at the live images that come to his mobile terminal. The images can be static images that keep refreshing at regular intervals or as video.

Push applications
Most of the architectures discussed above are based on Pull Mechanisms. For a Push based service there has to be a SMSC. If the information has to go as an SMS message, there has to be an additional gateway between the Mobile Terminal and the server. This gateway is called the Push Gateway. SMS based push applications already exist. WAP based push applications are just beginning as PUSH has just been introduced in WAP 1.2 and there are few WAP 1.2 compliant phones in the market. Many GIS-based push applications are in the same lines as the applications discussed above. Wherever the information is not being pulled from the server. For example giving Jobs to field officers who are on the move, Push can play a major role to deliver the information to the client.

Advantages
There are certain definite advantages Mobile Mapping has over traditional map-display systems. Mobile mapping provides access to map related information anywhere anytime. The data itself that is being accessed is current, updated and stored centrally in a single location. Therefore it is convenient medium of dissipating information. It is a secure and private medium too. The additional advantage here is the scope of providing Location-based services; as the location of the user would be known by one of the location finding systems enumerated above. The mobile user would not require much infrastructure/hardware as he would normally require to access Map information.

Limitations
There are limitations and blocks in the progress of this mobile display mechanism. Every non-voice service has been hindered or delayed by the inability of the handset vendors to ship product in time and in volume The limited resources on the Mobile Terminals would restrict some features that are otherwise available on the desktop computers.

The actual speeds promised by 2.5G and 3G systems are much lower than their theoretical maximum. Few factors that may hinder the development of such systems from a developer’s point of view are that for networks like WAP there are lot of Gateway dependencies and non-conformance of standards (WAP etc.) by OEMs of phones and PDAs

Future Trends
With greater bandwidths (3G and 4G) and faster Mobile Internet access, one can see lot of multimedia content being delivered on the mobile terminals. Push based mapping services using GPRS could roll out in near future. IVRs that would be an Automated-Vocal help desk could be accessible through toll-free numbers. XML and J2ME would be the good development platforms. IP technology now offers the prospect of transmitting traditional voice communication services known as Voice Over IP (VoIP). This is a service concept with revolutionary potential for the voice communication business. . There can be many voice-browser map portals where the user can speak to the web site and hear to the map information.

Conclusion
As wireless Internet access becomes more popular and cheaper, mobile mapping will grow penecontemparaneously along with Wireless Internet. Providing Map content to the Mobile Terminal is easy, there can be issues regarding providing Wireless Internet service. Many studies indicate that in a couple of years time there will be more people accessing Internet through Mobile devices than desktop computers, and there will be lot of mobile devices than land-phones itself. This would create a lot of demand for Location based services.

Mobile Mapping is a good contender to provide killer applications in this convergent world. As the first truly open standard for intelligent messaging services for digital mobile phones and other mobile terminals, the Wireless Application Protocol (WAP) will lead to a wireless data boom in the mass market.

Acknowledgements
We thank Mr. B.V.R. Mohan Reddy, Managing Director, InfoTech Enterprises Limited who has been a constant source of inspiration for all of us. We acknowledge the contribution and encouragement of Mr. U.Srinivas, Mr. Rajeev Lal and Mr. Joseph.