What is GIS?
Loclyn Anderson
GIS Coordinator
City of Tallahassee, Utility Support Services GIS
2602 Jackson Bluff Road,Tallahassee, FL 32304
Mark Haro
GPS Specialist
City of Tallahassee, Utility Support Services GIS
2602 Jackson Bluff Road, Tallahassee, FL 32304
Abstract
A growing number of utility personnel are being exposed to information technology (IT). It has
become important to communicate the basic concepts of GIS, coupled with it’s applications as
related to AM/FM projects. This paper will explain the fundamental concepts, terms and
planning requirements for a Geographic Information System (GIS). Understanding the
differences between computer aided design (CAD), geographic information system (GIS) and
automated mappinglfacilities management (AM/FM) technologies can provide a solid
foundation for utility IT projects. This will result in utility personnel being more adept at
comprehending and utilizing diverse information.
What is GIS
“Geographic Information Systems (GIS) are computer based systems that are used to store,
retrieve and manipulate geographic data”. As a definition, this statement is acceptable and true.
To the novice, the statement can prove more confising. As more industries are exposed to these
types of systems, it is important to understand completely what is GIS. The best way to begin is
to first learn GIS terminology. Secondly, we must gain an understanding of the functions and
concepts of a GIS. Thirdly we must learn how to acquire planning information to implement
GIS.
GIS is a term often used in the technical work force. Oi%n we will not admit to our lack of
understanding or knowledge about such a “hot” topic. The first step in better comprehending the
ideas of GIS is to become familiar with GIS terminology. Words like “accuracy, feature,
rubbersheeting, node, geocode, and COGO” are often terms we hear but do not always
understand. In the attached glossary of terms, you will find the definitions of words often used
by the GIS community. Space is also available to add words of your own. Study these terms in
order to be more conversant on matters of GIS as well as grasp abetter understanding of GIS
concepts.
The second step is to learn and gain an understanding of the fimctions and concepts of a GIS.
This can seem like the most diflicult part of the learning process, but in reality is very simple. A
GIS has four(4) major components: data entry, data management, data manipulation and
analysis and finally, data output. Let’s explore each area more closely.
Data Entrv or Data Inrmt:
This component is often referred to as the data conversion or data
collection stage. Normally, data exists on paper maps or hand drawn maps, electronic maps such
as AutoCad maps, aerial photographs, or even satellite images. You may have data that has not
been captured yet, or data that has been stored only in the minds of veteran employees. In order
to have a successful GIS we must first put all data into one system. In most cases, this would
require some sort of conversion, or merging all data into one system. Geographic accuracy may
or may not be an issue. GIS, however, is a tool that can assist in locating and mapping facilities
with a higher level of accuracy, thus providing integrity to your data.
Data entry or conversion can be the most costly part of your GIS project. It could take months
or even years to initially collect and convert data. This is when you must decide what your
accuracy requirements will be. After this decision is made, standards must be set and followed.
Once data is entered or converted with inaccuracies, datawill output inaccuracies.
Data collection may be performed by field crews gathering data manually. GPS is a tool often
used by companies to capture accurate data along with information about the location or facility.
This is called attribute data or feature data. Attribute data is stored in the database and is related
geographically to a point or feature on the earth’s surface. By using a tool like GPS, capturing
accurate data is an tiordable possibility and is an easy way to update data.
Data Manamnent:
Data management is the process of storing and retrieving data from a data
base. Once data is captured or converted it must be managed and maintained. Updates and
changes must be made on a regular basis in order to ensure data integrity. Standards must also
be in place so data is always up-to-date. A GIS is more usefil if current data is available for
analysis. Planning the structure of the database is critical because it will determine the ease and
speed of data retrieval. Good data is the key to a solid and successful GIS.
Data is often forgotten after the initial conversion or collection. When this happens, it slows or
halts GIS projects because users want current data for analysis. Therefore, once data is captured,
converted or entered, it must be maintained and managed. Users who are responsible for
updating and maintaining data should be identified early in the project to avoid data disasters.
Data Manitmlation and Ana.hsis: Specific GIS applications are the most common way to
manipulate and analyze geographic data. Simple database queries are also ways to obtain
information stored in a GIS. This component concentrates on what you want from the data.
Data can be manipulated in many ways. It is in this stage that the people using the data dictate
what they want from the data and then applications are written to perform those functions.
Applications can include standard queries, map generation and production, marketing analysis,
reports, data entry forms, work order tracking, trouble call routing, and dispatching. The
applications are limited only by project budgetary constraints and time.
Data OutPut:
Data output is best defined as data in the form of maps, tables, or text in both
hard copy (paper copies) or sofl copy (electronic files). This component is what most users want
first. Understanding that the data collection and conversion is first will help produce better
quality output. Visuals are important tools in business. A GIS can produce great visuals if the
data is accurate and well maintained. Remember, without data, a GIS can not exist.
How do I plan for a GIS? How do I implement a GIS? These questions are often asked to late
in the process. In order to successfully implement a GIS, you must first spend time planning for
what you want your GIS to do. GIS can perform many functions. It can house a landbase,
infrastructure, facilities, utility lines, and countless other layers of data. These systems can be
polluted with bad data which cause fictional problems with hardware and sof~are. Planning
in advance can prevent many of the problems associated with a GIS.
