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Essential Elements of a GIS
Geographic information systems are designed to handle information regarding spatial
locations. In this chapter, we will introduce the essential components and
functional/procedural elements of a GIS.
Components of a GIS
- hardware: The computer on which a GIS operates. A wide range of hardware types,
from centralized computer servers to desktop computers used in stand-alone or networked
- software: GIS software provides the functions and tools needed to store, analyze,
and display geographic information. Key software components are
- tools for the input and manipulation of geographic information
- a database management system (DBMS)
- tools that support geographic query, analysis, and visualization.
- a graphical user interface(GUI) for easy access to tools.
- Major GIS softwares: Arc/Info by ESRI, Intergraph by Intergraph, MapInfo by MapInfo, etc.
- data: Possibly the most important component of a GIS is the data. Geographic data
and related tabular data can be collected in house or purchased from a commercial data
provider. A GIS will integrate spatial data with other data resources and can even use a
DBMS, used by most organizations to organize and maintain their data, to manage spatial
- people: GIS technology is of limited value without the people who manage the
system and develop plans for applying it to real world problems. GIS users range from
technical specialists who design and maintain the system to those who use it to help them
perform their everyday work.
- methods: A successful GIS operates according to a well-designed plan and business
rules, which are the models and operating practice unique to each organization.
GIS Functional/Procedural Elements
- Data acquisition : The process of identifying and gathering the data required for
- gathering new data by preparing large-scale maps of field observations, or by
contracting for aerial photography.
- locating and acquiring existing data, such as maps, aerial and ground photography,
surveys of many kinds, and documents, from archives and repositories.
- Preprocessing : Manipulating the data in several ways so that it may be entered
it into the GIS.
- data format conversion: extracting information from maps, photographs, and printed
records and then recording this information in a computer database.
- identifying the locations of objects in the original data.
- data management : The creation of and access to the database itself.
- manipulation and analysis : focus of attention for a user of the system. The
analytic operators that work with the database contents to derive new information.
- product generation : Final outputs from the GIS like statistical reports, maps,
and graphics of various kinds.