GIS/WEB DESIGN FOR INTERNET/INTRANET DATA SHARING
Piero BOCCARDO (*), Giuliano COMOGLIO (*), Nadia CORGIAT LOIA (*)
(*) Dipartimento di Georisorse e Territorio
Politecnico di Torino
C.so Duca degli Abruzzi, 24
10129 Torino
E-mail: boccardo@polito.it
Commission VI, Working Group 3
KEY WORDS: GIS-WEB, DIGITAL CARTOGRAPHY, DATABASE
ABSTRACT:
The current net technology has improved the level of territorial information sharing thanks to the development of software for
Intranet/Intemet spreading of GIS data. This work is part of that framework as a prototype of a GIS/WEB application for
Geographical Information Systems net distribution.
1. Introduction
The World Wide Web is nowadays the broader set of electronic
information in Internet. The main Web’s objects characteristic
is, apart from the information conveyed themselves, to contain
hyperlinks toward others objects; these virtual links constitute
the so-called WEB.
The simpler Web object is a hypertext, which is an electronic
text document. This document, in some part of the text, allows
some links to other objects. A set of organised hypertext or
HTML documents is called Web site; a web site can be
displayed by means of software called Browser (for example
Netscape, Explorer, etc.); all the pages are not in a predefine
sequence but, by means of links, is possible to read them in
different orders.
HTML pages are essentially of two different types:
1. Static pages available before client request; the web server
display them without any particular action. User can access
a static page by composing the URL
(http://www.azienda.it/home.htm; see fig. 1), otherwise it
is possible to click the ipertext link. The request is sent to
the server that will display the HTML page.
HomeJitm
http о m e co m p ute r/h о me .htm
Client
network
Server
(Windows NT Workstation)
2. Dynamic pages. They are created after a precise user
request. The Web browser collect all the information taken
from the page and, using a confirmation button the
information is sent to a Web server. The Web server
activates a script in order to elaborate the information;
otherwise it can build a specific query, which retrieve the
data in the database. The results will be displayed to the
user by means of an HTML page. Two different interfaces
are used to manage dynamic pages: ISAPI {Microsoft
Internet Server Application Programming Interface) and
CGI (Common Gateway Interface).
Figure 2 - HTML dynamic page (ref: Microsoft Peer Web
on-line guide)
Figure 2 shows how to send an order using the Internet
Database Connector (IDC), an ISAPI application, used in
this work to retrieve information in a database.
Figure 1 - HTML static page (ref : Microsoft Peer Web on
line guide
The operational framework
The present work, jointly carried on by Osservatorio Civis,
public body involved in the restoration of Genoa historical
centre, Intergraph Italia and Politécnico di Torino, regards the
design of a GIS Intranet distribution. Particular attention has
been paid to characterise the web site following different
specifications:
