Using XML-based Format in Wireless Spatial Databases 
- Ali A. Alesheikh*, Hossein Mohammadi^. Mehrnoosh Ghorbani^, Ehsan Mohammadi? 
GIS Department, Geodesy and Geomatics Engineering Faculty, 
KNT University of Technology, Vali-Asr Street, Mirdamad Cross, 1996715433, Tel: (498 21) 877 0218 
eJ? 
a. Assistant Prof.: alesheikh@kntu.ac.ir 
  
b. GIS Master: hmohammadi@globearray.com 
¢. GIS MSc Student: mehrnoosh shorbani&ivahoo.com 
d. GIS MSc Student: mohammadiehsan@ yahoo.com 
  
KEY WORDS: Web, Mobile, Spatial, Database, Vector 
ABSTRACT: 
Nowadays, sharing the huge amount of geo-data is the main GIServices challenge. However, the new generation of handheld devices 
together with the growth of wireless web network. provide a suitable platform for GIS to share the geo-services. The devices suffer 
from small screen size, limited input and output capability and limited memory. Moreover, users look for spatial information 
services that are currently rare in the devices. 
From one hand, wireless spatial services have to overcome wireless network and devices pitf 
alls, and on the other hand, they must 
introduce a system, in which, data transmission is fast and reliable and independent from platform regarding to diversity of devices. 
In addition to application itself, the data play a prominent role in this scenario. It is vital to generate and transmit low volume and 
simple data, especially when system is dealing with vector data. 
XML technology presents a simple and platform independent format to encode spatial data and any programming language is able to 
parse XML documents. 
This paper elaborates on the powerful aspects of XML format and its advantages in wireless database managing applications. A case 
study has been developed to a wireless spatial service in which, client/server architecture is developed. In this model client is a 
wireless device and sends requests to the server. Server generates XML document from desired area, according to the request. 
Generated XML carries the spatial data and attributes to the device. A Java code in client side interprets the XML content and 
displays the result. 
I. INTRODUCTION 
Nowadays, with the rapid growing in amount of the geo-data, 
the major problem ahead of the SDSSs (Spatial Decision 
Support Systems) is not the availability or generating the data 
anymore. The most crucial problem is updating and sharing the 
huge amount of the geo-data, which must be addressed. 
To solve the problems, GISs spread their services in ubiquitous 
environments. The most recent attempt of GIS researchers is to 
share the geo-data and geo-services in wireless environment. 
The wireless devices expand from a cell phone to a powerful 
PC; hence, the software components of the system must be 
compatible with the diversity of the hardware, platforms and 
operating systems. One of the most important components of 
the wireless GIS is geo-data. Dealing with geo-data is different 
from other data contents. The geo-data is special because of 
handling spatial and aspatial data beside each other, and 
graphical presentation of spatial data. To deal with the diversity 
of the devices and gco-data characteristics, XML (eXtensible 
Markup Language) introduces an appropriate data format. 
XML provides a platform independent meta-data. Modeling the 
data in XML, brings the characteristics of the XML to the data. 
Simplicity, openness, self description, and standardization are 
the most prominent advantages of XML over other data 
formats, especially in web-based systems. XML parsers are 
responsible for parsing the tags and contents of the XML 
document. XML schemas define an overall structure for the 
data. XSL provides a mechanism to map the XML data 
contents to the interested form. 
This paper tries to investigate the shortcomings of the wireless 
handheld devices in dealing with geo-data, data transfer 
obstacles in wireless environment, and a platform independent 
data format for diverse software/hardware. The paper 
eventually, introduces a practical method to overcome the 
obstacles of wireless GISs from geo-data viewpoint. 
The case study, carried out in this paper, is put forward along to 
implement the geo-database part of a wireless GIS. The main 
database in server-side of the system converts the invoked 
instance of data to XML and sends back the XML document to 
the client, XML parser in the client-side parses the document 
using an application schema. The parsed contents are displayed 
in screen using an XSL (eXtensible Stylesheet Language). 
2. WIRELESS GIS ARCHITECTURE 
The wireless GIS architecture uses application logic type 
(thick-client) approach of client/server architecture. In this 
approach the main database resides in server-side and may 
consist of any traditional data formats (Figure 1). The server 
side application functions separately from client application. 
Server-side application is responsible for listening to the 
requests of user and generating XML documents from the main 
database. The client side application consist of three modules, 
GIS module comprising of GIS functions, XML parsing and 
interpreting module, and display module. 
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