Getting started with GIS

Getting started with

G S

Submitted by:

Pattan Imran Khan

IntroductionGeographical Information System

The acronym GIS stands for Geographical

Information System.

GIS consists of two distinct disciplines,

namely, Geography and Information System.

GISGeography Information system

&

What is Geography?

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?

What is Information

System?

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.

What is a GIS?

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

Software

Data

Documentation

Users

Hardware

• 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

Areaspoint

1,6

2,5

5,4

4,1

7,105,9

4,7

6,68,6

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

DataBases

Step 3 : Manage

Examples :

PostGIS

MySQL Oracle

Step 3 : Manage

Printed Maps

Dynamic or Interactive Maps

Step 4 : Present

GIS Applications

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

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