Geographic Information Systems (GIS) and the Internet

Introduction

A geographic information system (GIS)
consists of hardware, software, and users to support the capture,
storage, retrieval, update, management, manipulation, analysis,
display, and modeling of geo-spatial data. Before GIS, researchers used
films and mylars to manually overlay spatial information. The
integration of spatial information with non-spatial attributes
(variable) is a critical component of a GIS. Many large complex tasks
are accomplished much more quickly by a GIS than by a human working
alone. A GIS is a “smart map” system linking databases to digital maps.
Several names, such as spatial information system, land information
system, natural resource management information system, planning
information system, and environmental information system, have been
used for GIS, giving a “high-tech” feel to spatial information.

GIS and related technologies are becoming more available to many users
in different disciplines through the World Wide Web. GIS and related
technologies will help greatly in the management and analysis of
worldwide data and allow better understanding of environmental and other processes around the world. Desktop GIS has been the system of
choice, but it has many limitations including high cost, high learning
curve, and limited public access of data. On the other hand, an Internet-GIS
(i-GIS), which focuses on distributed geographic information services
for the decentralization of geographic information management, has many
advantages including decentralized data storage, wider user access, and
convenience. The advent of the Internet and computer technology has
made it possible to share and analyze data through World Wide Web–based
management systems. The Internet and GIS have been used to download,
preprocess, review, modify, and analyze up-to-date geographic data
since the early 1990s. Although today’s Web-based systems offer an
excellent opportunity to use GIS beyond the home and office, existing
i-GIS map servers do not provide the complex analytical functionality
required by many users. Internet-GIS is becoming one of the most
rapidly evolving fields in e-commerce. For organizations and
institutions, i-GIS will provide easy access to GIS data with
decentralized databases.

Future GISs, including automated processing at offices and homes, will
likely be a part of our daily lives. When you walk into your house, the
system will know where you are and what kinds of things you might want
to do, such as turning on specific appliances or planning a trip using virtual environments.

A Brief History Of Geographic Information System

GIS technology, which began in the 1960s, has been one of the most
rapidly evolving fields during the past two decades. The Canada
Geographic Information System (CGIS) and the Urban and Regional
Information Systems Association (URISA) were developed in 1963, the
latter a nonprofit association using GIS technology in public works and
services and local and state planning agencies. The Harvard Laboratory
for Computer Graphics established in 1964 pioneered many aspects of
GIS. In 1965, Synagraphic Mapping System (SYMAP), an automated computer
mapping application system, was developed at the Northwestern
Technology Institute and at the Harvard Laboratory for Computer
Graphics. In 1967, the United States Central Intelligence Agency (CIA)
developed an Automatic Mapping System (AUTOMAP), a map compilation
system at the global level. The establishment of several companies,
including the Environmental Systems Research Institute (ESRI) and
Intergraph Corporation in the United States and Laser-Scan in the
United Kingdom, initiated worldwide commercial applications. In the
1970s, several GIS programs and systems were established and the first
Landsat Multispectral Scanner (MSS) satellite (originally known as
ERTS-1) was launched. In 1977, the U.S. Geological Survey developed one
of the first spatial data formats, the digital line graph (DLG). The
establishment of other companies, such as ERDAS, which was founded in
1978, and the first vector based GIS data structure, ODYSSEY GIS, which
was developed at the Harvard Lab, provided major advances. In 1981,
ESRI introduced one of the earliest commercial GIS software packages,
Arc/Info, which has become by far the most widely used GIS software
including topological consistency in GIS data sets. During the same
year, the global positioning system (GPS) project became operational.
In 1982, the development of the Geographic Resources Analysis Support
System (GRASS), an open source/free raster–based GIS software, was
begun at the U.S. Army Construction Engineering Research Laboratories,
a branch of the U.S. Army Corp of Engineers. During the late 1980s,
several GIS companies such as MapInfo (1986), SPOT satellite program
(1986), Idrisi project (1987); a GIS journal; the International Journal
of Geographical Information Systems (1987); a GIS conference; the first
GIS/Land Information Systems (LIS) conference (1988); and data formats
such as the first public release of the U.S. Bureau of Census TIGER
(topologically integrated geographic encoding and referencing) digital
data were created. The U.S. Geological Survey defined one of the latest
spatial data formats, the Spatial Data Transfer Standard (SDTS), in
1992 (Federal Information Processing Standard 173). During the 1990s,
GIS became one of the most rapidly evolving information technology (IT)
fields. Today GIS is being used in many disciplines including the hard
sciences; the engineering, medical, and social science fields; at every
level of government including the local, state, and national levels;
and in business and industry.

One of the important issues in GIS is meta-data standards, which
describe the origin, content, quality, condition, and other
characteristics of geospatial data. The Federal Geographic Data
Committee (FGDC) coordinates the development of the National Spatial
Data Infrastructure (NSDI). According to the FGDC, “the NSDI
encompasses policies, standards, and procedures for organizations to
cooperatively produce and share geographic data. The 17 federal
agencies that make up the FGDC are developing the NSDI in cooperation
with organizations from state, local and tribal governments, the
academic community, and the private sector.” The FGDC approved the
Content Standard for Digital Geospatial Metadata (FGDC-STD-001–1998) in
June 1998 (http://www.fgdc.gov/metadata/metadata.html). The FGDC has created a Web-based FGDC Metadata Entry System (http://130.11.52.178/metaover.html)
“to stimulate the creation of basic FGDC-compliant meta-data records
for the cataloging of spatial data sets.” Also, the NSDI/FGDC National
Geospatial Data Clearinghouse Information Resource Web site (NSDI/FGDC,
1998) node has been created to provide links to spatial data. The
Clearinghouse Activity is a decentralized system of servers located on
the Internet which contain field-level descriptions of available
geospatial data.

Desktop Geographic Information Systems

There are several definitions of GIS (Chrisman, 1997). GISs are a form
of information system applied to geographic data and consist of several
interconnected subsystems including data storage, management, and
processing; data analysis and manipulation; and output subsystems used
to capture, store, retrieve, update, process, analyze, model, and
display spatially referenced (georeferenced) data systematically. A GIS
is different from a database management system (DBMS) in terms of
capability. DBMSs store and process mostly non-spatial data. On the
other hand, a GIS, which may also include relational database
management systems (RDBMS), not only processes geo-spatial data but
also link non-spatial (or attribute) information to spatial data. A GIS
enables institutions and managers to manipulate geographic data more
efficiently and to make informed decisions for planning purposes.

Components of a GIS

A GIS is an integrated system consisting of hardware, software, data,
and users (Aronoff, 1995; Bolstad, 2002; Figure 1). GIS hardware
includes computers, input devices, data storage, display, and output
systems. GIS software is the main part of the system and provides for
spatial data management, manipulation, analysis, display, and output.
Data input devices include digitizers, scanners (flat-bed or drum), and
imaging systems such as digital cameras. Data storage units are tape
and disk drives (hard disk and floppy), CD/DVD drives, and other
optical and magnetic storage devices. GIS display and output devices
are monitors, projectors, printers, and plotters. GIS output can be in
hard-copy (paper maps, tables, etc.) or softcopy format (digital data
and images).

Desktop GIS Versus INTERNET Or INTRANET GIS

Although desktop GIS has been a choice for many institutions requiring
analysis of complex geographic databases, it has many limitations
including cost and public access issues. Before the introduction of
i-GIS, many companies, educational institutions, and local, state, and
federal agencies started to use intranet GIS to overcome some of the
limitations of a traditional GIS; however, an intranet based GIS does
not usually allow full public access. On the other hand, i-GIS has many
advantages, including decentralized data storage and data maintenance,
wider data access, and convenience. Web-based systems offer many
opportunities to go beyond the home or office. Existing i-GIS map servers do not facilitate analysis of complex geographic databases,
however, because some technological (e.g., software and bandwidth and
speed) issues and specific user requirements. Today’s Web based IMS
systems offer data browsing, retrieving, updating, displaying and
querying, map-making, address matching, and route finding. Most of them
and probably new ones will be able to facilitate analysis of complex
geographic databases in the near future when some of the technological
limitations that exist today are overcome.

GIS Data Users And The Internet

GIS has been used at local, state, and national levels. The power of a
GIS is highly correlated with its accessibility. A desktop GIS is
mostly used by experts. Therefore, a desktop system is generally
limited to a smaller group of people. A Web-based GIS can be accessed
by millions of people using the Internet. Most people do not need to
know all the aspects of GIS. Many probably do not realize that they are
using an i-GIS (e.g., a map server such as MapQuest [http://www.mapquest.com/] or MapBlast! [http://www.mapblast.com/]
providing maps and driving directions) when they request a best route
for a destination. Most GIS data are dynamic, therefore regular
updating of data is required in most instances. When a user desires a
best route, a map server should not contain outdated data. If a bridge
is out, a GIS cannot generate alternate routing unless its database is
updated promptly.

During the early days of GIS, data were created and used predominantly by federal agencies. The U.S. Geological Survey (http://www.usgs.gov/), the U.S. Census Bureau (http://www.census.gov/), the Central Intelligence Agency (http://www.cia.gov/), and the National Imagery and Mapping Agency (http://www.nima.mil/)
have generated many data formats and databases. During the 1970s and
1980s, GIS data were mostly available on magnetic tapes or floppy
disks, which were delivered in days or weeks and were costly. The
Internet was used to transfer data to private users, but during the
late 1980s and early 1990s the main users of GIS data and the Internet
were government agencies and research universities. With the
introduction of the Web in the early 1990s, many institutions started
to provide data to the public over the Internet. During the past
decade, local and state governments, as well as the private sector,
helped create many datasets that were available to the public. GIS
became a part of our daily life and a multi-billion dollar industry in
the late 1990s. Most of the GIS data were provided free via the
Internet. The USGS stopped serving some of the data that were
originally provided from its Web site and transferred some datasets to
private companies. These companies provided GIS data free or charged
minimal fees for faster service (i.e., faster Internet connections or
delivery) because their sites were financially supported by
advertisements. When advertising companies started to cut their
advertisement spending, GIS data providers started to charge more for
their services.

INTERNET Versus INTRANET GIS

The term intranet is usually used to describe applications and
protocols of the Internet used to share and move information within an
organization’s boundaries. Intranet systems have been used to serve and
share GIS data within institutions because data could not be made
public because of security issues and other technical limitations of
the Internet. Many large corporations have Intranets for their
employees. Intranets may be connected to the outside world via a
firewall, which allows a protected gateway between an organization’s
internal network and the Internet. An Intranet typically has several
advantages over the Internet:

  • Secure connections: Intranet provides private internal networks such as
    local area network (LAN) or wide area network (WAN), which are
    protected from outside Internet users by a firewall.
  • Easier control: Intranet is much easier to handle in terms of protocols and connections.
  • Higher data transfer speed per unit (bandwidth) cost: Intranet provides
    higher and broader bandwidth per unit cost than the Internet.

For large companies that have offices in various cities or states,
Intranet services may not be sufficient. Several network providers
offer virtual private network (VPN) services, which are used on the
public or open Internet, to companies that have more than one business
location. These companies use point-to-point tunneling protocol (PPTP)
to make secure connections between VPN nodes. Because the Internet is
an “unsecure” open network, the PPTP is used to transmit data from one
VPN node to another securely.

As stated previously, GIS data are dynamic and must be updated
regularly. Several county and city agencies started to update and share
their data with local and state agencies via the Internet in the
mid-to-late 1990s. To use a GIS over the Internet, RDBMS with
object-oriented extensions, software systems with cross-platform
portability, client-server architecture, and other technologies had to
be developed.

With the growth of the Internet, the distribution and viewing of data
online are now an integral part of many projects. The integration of
GIS with the Internet is an inevitable trend that is becoming a
reality. Several companies have developed ActiveX-based distributed
applications in addition to the standard IMS-based systems. The
ActiveX-based systems are similar to the IMS-based systems but use a
Web browser. A user connects to a Web server having “desktop” GIS
software using a browser and loads the ActiveX component to run a GIS
mapping application software remotely. Using the ActiveX component has
many advantages including the use of data on a local computer without
using remote disk mount utilities, which can be difficult to maintain.
This technique is ideal for local or state governments that may require
quick access to data (i.e., ownership or parcel data).

Desktop GISs are not appropriate for modern distributed network
environments because of their closed architecture. Distributed GIS
services can provide many capabilities and functions for data storage
and management (Brown, 1999; Huang, Jiang, & Li, 2001; Huang &
Worboys, 2001; Tsou & Buttenfield, 2002). In addition to the
ActiveX-based systems, there are also other technologies, such as
Java/VRML (virtual reality modeling language), common gateway interface
(CGI), extensible markup language (XML), .NET, and other services used
to support the development of i-GIS.

Internet Map Servers

It is expensive to maintain and update large GIS databases. One of the
goals of IMSs is to access large spatial databases in real time and to
provide the data to the public. Most IMSs have been used to browse,
display, query, and retrieve spatial and attribute data. Some IMSs can
also be used to update GIS data. There are several commercially
available IMS software packages, which offer several GIS functions
including routing, regional, and local- or street-level mapping, and
simple querying and analysis.

IMSs can be classified into two major groups, static and dynamic. A
static IMS provides maps in GIF, JPEG, or other image formats. Map
images (usually in the form of a digital raster graphics in TIFF
format) are created using desktop GIS software or scanned from existing
hard-copy maps in advance and served over the Internet using a Web
server and basic Web browser formats (e.g., HTML code). Dynamic systems
usually update map images based on users’ requests or based on current
data to be made available to the users. Only dynamic IMSs provide the
functionality of local standalone GIS databases. Some dynamic systems
allow users to create their own maps or perform limited geographic
analysis. Several local and state governments provide data including
parcel tax data, current conditions (roads, crime events, and
patterns), environmental conditions such as lake or river levels and
fire information, and other maps to the public using IMSs.

Today there are many commercial Web-based IMS systems such as AltaMap
(GeoMicro), ArcIMS, ArcView Internet Server, Autodesk MapGuide,
BeyondGeo, Demis Map Server, EarthKey, FreshMaps, GEO-Data Explorer
(GEODE), GenaWare, GeoServ.org, InterroMAP, Map- Info MapXtreme,
MapObjects IMS, Maptitude for the Web, Map-TV, Oracle, VectorEyes, Web
Mapper, and WebView. Some IMSs are available free of charge: ALOV Map,
GeoTools, Imapper, Jshape, MapCiti, MapIt!, and Mapserver. Currently,
most of these IMSs have some technological limitations. In the future,
new IMSs will be able to overcome some or most limitations to
facilitate analysis of complex geographic databases remotely via the
Internet.

The Future Of Internet GIS (I-GIS)

One of the difficulties of offering distance-learning courses,
particularly IT courses via the Internet, is the availability of
software used over the Internet (e.g., the ability to use software like
Excel or Word perfect on a different (remote) computer using a Web
browser). Much research is being conducted to integrate desktop and
Internet based software packages. Geographic information science (GISc)
is one of the fields that will benefit the most. Integration of desktop
GIS and i-GIS is still an evolving issue. More and more companies have
offered i-GIS packages over the last several years, and shareware
software packages are being circulated. These new developments will
bring several other issues including data and computer security,
meta-data, and data format issues to the forefront.

A standard language for i-GIS is necessary to have systems compatible
across the Internet. The Open GIS Consortium (OGC), an international
industry consortium of several hundred companies, government agencies,
and universities participating in a consensus process, has been
established to develop publicly available geoprocessing specifications
and to deliver spatial interface specifications that are openly
available for global use (http://www.opengis.org/).
OGC’s OpenGIS specifications for interfaces and protocols, the
foundation for “interoperable” geoprocessing, have become widely used.
Development of XML in 1996, which has been a W3C standard since
February 1998, provided a tool for OGC to develop a geography markup
language (GML), a new common geospatial data format. OGC specified GML,
an XML extension for encoding the transport and storage of geographic
information, including both the geometry and properties of geographic
features in 1999. GML, which is based on OGC’s abstract model of
geography, is becoming a standard for i-GIS. The GML 2.5 version, which
was approved in September 2001, incorporated various schema revisions.
The latest version, GML 3.0, is currently in progress.

Internet-GIS is becoming one of the most rapidly evolving fields in
e-commerce. GIS applications in wireless e-commerce integrating GPS and
GIS technologies to direct customers to the nearest locations such as
restaurants, gas stations, and hotels and to track vehicles for
automatic vehicle location are now available. For institutions, i-GIS
will provide easy access to GIS data without duplication (decentralized
database). For developers, i-GIS will facilitate a new challenge as
well as an opportunity to increase their market share. Users will
become proficient at bringing GIS to the Web and become experts in data
import and export, query, manipulation, analysis, output, and
synthesis. More important, users may become project managers who will
realize the value of i-GIS for quick decision making. Existing i-GIS
map servers are presently not able to fully analyze complex geographic
databases. In the near future, we will be able to use a GIS from
wherever we are, at home or in a different city. Still, it is likely
that a Webbased i-GIS will never be “complete.” Upgrades, patches,
updates, and changes will always be necessary. As our collective
experience and understanding of the technology grows daily, we will
never be satisfied with the current technology and will look for better
alternatives.

Conclusion

Today GIS is being used in almost every field that emphasizes spatial
data collection, analysis, manipulation and integration, analysis, and
modeling. Desktop GIS has been the system of choice for many
institutions requiring analysis of complex geographic databases.
Nonetheless, it has many limitations including startup cost, learning
curve, management difficulty, and public access issues. On the other
hand, i-GIS, using decentralized data storage, provides easy access to
GIS data without duplication. With the growth of the Internet,
distribution and viewing of data are now an integral part of many
projects. The integration of GIS with the Internet is still an evolving
issue and an inevitable trend that is becoming a reality. Although
today’s i-GISs do not offer the full capabilities of a desktop GIS,
partly because of software limitations and the bandwidth and speed
available to most Web users, future i-GISs will include automated GIS
processing and will be a part of our daily lives.

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