RESEARCH ON A DISTRIBUTED ARCHITECTURE OF MOBILE GIS BASED ON WAP
Wang Fangxiong*, Jiang Zhiyong”
* Research Centre of Spatial Information and Digital Engineering, Wuhan University, 129 Luoyu Road, Wuhan 430079,
China. wfxwhu@163.com
b = : . . : Y = . : . 7 : E
State Key Laboratory of Information Engineering in Surveying, Mapping and Remote Sensing, Wuhan University,
129 Luoyu Road, Wuhan 430079, China. houyingzi@sohu.com
Commission VI, WG VI/4
KEY WORDS: Mobile GIS, Architecture, J2EE, WAP, Mobile Internet
ABSTRACT:
Mobile Geographical Information System (Mobile GIS) is a Geographical Information System based on mobile computing and
mobile Internet. It is not a conventional GIS modified to operate on a smaller computer, but an extension of Web GIS to mobile
Internet including wireless Internet/Intranet and mobile communication network. But architectures of Web GIS are unsuitable for
Mobile GIS, because of several bottlenecks such as the low-bandwidth of wireless network, the diversity of mobile devices, limited
processing power and screen display limitation of mobile devices and the diversity of mobile system platform. So the research on the
architecture of Mobile GIS is hot in the GIS field. WAP-based Mobile GIS can be described as mobile users can perform the almost
same functionality as of Web GIS but in a mobile environment at any time, any place and without the limitation of operating system
and wired link. In this paper, a distributed architecture for WAP-based Mobile GIS is proposed. Using Java Servlet Engine
technology and spatial information Web caching mechanism at the fat server side, the architecture based on J2EE is composed of
four logic tiers: presentation tier, WAP service tier, application tier and data service tier. A prototype system based on the
architecture has been developed. It can successfully work on WAP phones, which proves that the architecture is feasible.
I. INTRODUCTION
Since 1990, geospatial information technologies and mobile
wireless Internet have been rapidly developed. It is easy to see
that the integration of geospatial information and mobile
Internet is inevitable, which is simultaneity driven by market
demands and technologies (Li Deren, et al. 2002). The
integrated system is designed to work on mobile intelligent
terminals, and brings new dimension - at any time, any place -
to access geospatial and attribute information in GIS. It is called
Mobile Geographic Information System (Mobile GIS). Mobile
GIS offers another new perspective for the use of GIS and
further extends the “office” GIS works in mobile environment
(Shi Wenzhong and Kwan Kawai, 2002). Mobile GIS was carly
applied to assist office and collect data in the field (Ness S. T.
Lee, 1993; K. North, 1997). It is not a conventional GIS
modified to operate on a smaller computer, but a system build
using a fundamentally new paradigm (David Maguire, 2001). It
extends unlimited information on the Internet and powerful
service functions of GIS to mobile devices, and can provide
mobile users with geospatial information services. Mobile GIS
creates a new channel of business practice, and thousands of
potential applications and services can also be developed.
Hence, it is exploring a new era of mobile geographic
information services.
The rest this paper is arranged as follow: WAP-based Mobile
GIS and its superiority to SMS/MMS-based Mobile GIS are
briefly introduced in Section 2. Three mainstream architecture
solutions for distributed systems are presented in Section 3. A
distributed architecture for WAP-based Mobile GIS based on
J2EE is proposed in Section 4. And a prototype system
implemented based on J2EE is presented in Section 5. Finally,
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the conclusion is drawn and outlook of WAP-based Mobile GIS
are discussed.
2. MOBILE GIS BASED ON WAP
Mobile” GIS can be simply divided into two’ categories;
according to currently popular solutions accessing to the Mobile
Internet. Thé one is based on Short Message ‘Service
(SMS)/Multimedia Message Service (MMS), the other is based
on Wireless Application Protocol (WAP).
SMS/MMS-based Mobile GIS (Ma Lingbin, ct al, 2002; Wei
Zhongya, etal, 2002; Zhang Jianqun and Liang Juanzhu, 2003)
can only be suitable for mobile phones with sample’ system
functions, ‘unfriendly graphical user interface (GUI), poor
information presentation and the restricted application fields,
because of the limitations of SMS/MMS such as restricted
carrying information, time lag, unfriendly interactive mode, and
so on.
On the contrary, WAP is a bear-independent international
standard protocol that has optimized for mobile devices with
limited display and small keyboards of mobile handsets and low
bandwidths of wireless networks, and. permits applications and
services to operate over all. existing and foreseeable wireless
networks such as GSM, CDMA, PHS, TDMA and WCDMA
(WAP Forum, 2002). The WAP specification encompasses a
relatively simple and compact version of XML (eXtendable
Markup Language) called WML (Wireless Markup Language).
which makes it possible to make requests to a mobile service
from a mobile terminal and return a map in the form of an
embedded bitmap (e.g. WBMP). So WAP-based Mobile GIS
has richer information presentation, friendlier GUI, more
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