Getting started with GIS

Getting
started with
G S
Submitted by:
Pattan Imran Khan

Introduction
Geographical Information System
 The acronym GIS stands for Geographical
Information System.
 GIS consists of two distinct disciplines, namely,
Geography and Information System.
GIS
Geography
Information
system
&

 The scientific study of the geospatial pattern and
process.
 The geography usually starts with 3 “W’s”
questions :
1. Where?
2. What is it like there?
3. Why do I care?

 It is an interactive combination of people,
computer hardware and software, communication
devices and procedures designed to provide
continuous flow of information to the people who
need information to make decisions or perform
analysis.

 A geographical information system is a system
which integrates hardware, software and data for
capturing, managing, analyzing and visualizing all
forms of geographically referenced information.
 In simplest terms it is the merging of cartography,
statistical analysis and database technology.

In short, a GIS is….
An information system (hardware, software,
data)
which enables us to apply lots of analysis models
to any geographical datasets
for generating derived information
that can be visualized as maps.

History & Development of GIS:
 The development of GIS was first started in 1832. One of the first
applications of spatial analysis is in Epidemiology.
 In 1854 John Snow depicted a cholera outbreak in London using
points to represent the locations of some individual cases,
possibly the earliest use of a geographic methodology in
epidemiology.
 The year 1960 saw the development of the world’s first true
operational GIS in Ottawa, Ontario, Canada by the federal
dept. of forestry and rural development, developed by
Dr. Roger Tomlinson (Father of GIS),
it was called the Canada Geographic Information System (CGIS).

London Cholera epidemic(1854):
Cholera death
Water pump

Key components of GIS:
 A GIS constitutes of five key components, namely
1. Documentation
2. Hardware
3. Software
4. Data and
5. Users.
 These five components need to be in balance to
function any information system satisfactorily.
GIS
Softw
are
Data
Docu
ment
ation
Users
Hard
ware
• Vector(Drawing)
• Raster(images)
• Descriptive(text/tables)
• Guides
• Procedures
• Specifications
• Standards
• End Users
• Administration
• Managers
• GIS Technicians
• Computer &
Peripherals
• Networks and
network devices
• Printing and
image acquisition
devices
• GIS applications
• databases
• operating system
• other software's

GIS data & Spatial data model:
 Data are the observations made from real-world
experiences, organized and processed in order to
make them meaningful, and convert into information.
 Data may have three modes:
1. Spatial data
2. Thematic or attribute or non-spatial data &
3. Temporal data.
 Spatial data may be represented by several GIS data
models.

Data model:
 A data model describes in an abstract way how data
is represented in an information system.
 In GIS there are two basic data models to input and
visualize data in the world of GIS. They are:
1. Raster data model &
2. Vector data model.

Raster data model:
 The raster data model divides the geographic space into a
regular grid of square cells, called pixels, with a number in
each cell representing the solid color fill of that cell in specific
sequence (row-column structure).
 Example of raster data may be:
Stored electronic image or
picture taken as an aerial
photograph or satellite image.

Vector data model:
 The vector data model is close to the traditional
mapping approach where the objects are
represented as points, lines or areas(features).
 The position of each object is defined by a series of
coordinate pairs.
Points
Lines
Areas
point
1,6
2,5
5,4
4,1
7,10
5,9
4,7
6,6
8,6
9,8
line
polygon
2,2
5 10
5
10
Vector model Raster model

Capture Analyze Manage Present
GIS Process

Global positioning system (G.P.S)
Step 1: Capture

Remote sensing
Active
Passive
Step 1: Capture

Photogrammetric techniques
Step 1: Capture

Examples:
ArcGIS QGIS MapInfo
Step 2 : Analyze

Examples:
PostGIS MySQL Oracle
Step 3 : Manage

Printed Maps Dynamic or InteractiveMaps
Step 4 : Present

Applications of GIS:
 Agriculture
 Archaeology
 Business
 Crime mapping
 Environmental science
 Engineering
 Journalism
 Military science
 Natural resource
management
 Geography
 Geology
 Meteorology
 Oceanography
 Law enforcement
 Public health
 History
 Sociology
 Urban/Regional planning
 Transportation

Getting started with GIS

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