Definition of GIS
Geographic Information System (GIS) is a computer based information system which
works with data referred by spatial or geographic coordinates. A geographic
information system is a well-designed framework for capturing, storing,
checking, analyzing, and displaying data related to geographic (Earth’s
surface) location.
According to the USGS (United States
Geological Survey), “A GIS is a computer system capable of
capturing, storing, analyzing, and displaying geographically referenced
information; that is, data identified according to location”.
Rhind (1989) proposes
that “GIS is a computer system that
can hold and use data describing places on the earth’s surface”.
Burrough (1986) proposes that “a set of tools
for collecting, storing, retrieving, transforming, and displaying spatial data
from the real world for a particular set of purposes”.
Components
of GIS
Five Components of Geographic
Information System (GIS)
1. People:
2. Hardware:
3. Software
4. Data:
5. Methods:
1. People: Without the people GIS
technology is of limited value, people operate the system and design plans to implement it. People in GIS
are technical persons like GIS managers, database administrators, analysts,
specialists and programmers, etc. Those people develop, design and maintain the
GIS work and those who use it. Various categorized people present in GIS
field-
Viewers- the people, who just use GIS for reference,
General users- these people use for business, services, and
making decisions (planners, scientists).
Specialists- GIS specialists provides technical support. They are
considering as the backbone of GIS and maintain process and analyze geographic
data.
2. Hardware: Hardware is a computer that runs GIS software. There are different types
of computers nowadays, be it desktop or server based. ArcGIS Server is a server
based computer where GIS software is run on a network computer or cloud based.
For computer to perform well all hardware components must have high capacity.
Major hardware components are
i. Motherboard: Major hardware
parts are installed or it is a place where all elements get hooked
up.
ii. Hard Drive: Hard drive also
known as hard disk, where all the data place to stored.
iii. Processor: Processor is the
major component in computer, it performs calculation. It is called as Central
processing Unit (CPU).
iv. RAM: Random Access Memory
(RAM) where all running programs load temporarily.
v. Printer: It is output device
and used to print image, map or document. There are various type of printer
available in market.
vi.
External Hard Disk: These are bearable storage space such as USB
drive, DVD, CD or external disk
vii. Monitor: It
is a screen for displaying output information. Nowadays there are different
types of monitors: CRT (cathode ray tube), LCD (Liquid Crystal Display), LED
(Light Emitting Diodes) and more.
3. Software: The next component is GIS software which provides the necessary functions
and tools for storing, analyzing and displaying geographic information. It
helps to query, edit, run and display GIS data. It uses RDBMS (Relational Database
Management System) to store the data. Few GIS software list: ArcGIS, QGIS, SAGA
GIS, GRASS GIS, ILWIS.
Key Software Components:
- RDBMS: Relational Database Management
System to store GIS data. GIS Software retrieves from RDBMS or inserts
data into RDBMS.
- Query Tools: Tools that work with
database management system for querying, insertion, deletion and
other SQL (Standard Query Language).
- GUI: Graphical User Interface that helps user and Software to interact well.
4.
Data: The most important
and expensive component of the Geographic Information System (GIS) is the data
that is commonly known as the fuel for GIS. Probably the most time consuming
and costly aspect of starting a GIS is creating a database. GIS data is a combination
of graphic and tabular data. Data can be graphic vector or raster. Both types
of data can be created using free source GIS software or purchased.
A GIS will integrate spatial data with other data resources, and most
organizations can use the Database Management System (DBMS) used to organize
and maintain their data to manage spatial data. The process of creating GIS
data from analog data or paper format is called digitization. Polygons, lines
and points are created by digitizing raster image. GIS data can be raster or
vector.
GIS Data Types:
1.
Raster data: Raster image data in a cell-based
manner. It can be aerial photo, satellite image, digital elevation model (DEM).
Raster images usually store uninterrupted data.
2.
Vector data: Vector data are discrete. It
stores data in the form of x, y coordinates. There are three types of vector
data: line, point and polygon.
Errors in the data set
can add inconvenient and costly hours to a GIS implementation, and GIS analysis
results and conclusions are likely to be inaccurate. Therefore, if the relevant
information is missing from the feature and information related to the feature,
check the data. It can deal with omission errors or spatial errors such as
limiting minimum width or field information.
5.
Methods: For a GIS system to work properly, not only the
hardware, software and data required, but also an organized method is required
to use GIS technology. Procedures for answering questions are followed to solve
the question. An
efficient GIS technology is governed by a well-planned plan and business rules,
with each company's unique model and operating practice. GIS procedures include
how data can be accessed, stored, managed, processed, analyzed, and ultimately
presented as output for specific applications.
.
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