“G” “I” “S” • Geographic?

– Reality

– Spatial location, scale, and time

• Information? – Data and meaning of data

– Collections of facts, knowledge base, personal or collective values

• Systems? – Computers and methods

– Physical and conceptual entities or networks

• Science? – Knowledge, System of Knowledge

Geographic Information Systems Describing Our World

• We can describe any

element of our world

in two ways:

Attribute Information: What is it?

Species: Oak Height: 15m

Age: 75 Yrs

Location Information: Where is it?

51°N, 112°W

What is GIS/GISc?

• Complex Processes – management, analysis, and display of spatial data

• Software

• Hardware

• Spatial data

• People

• Procedures

• Inherent Spatial Links

• Interaction between Maps and Data

• Ability to Produce New Spatial Entities

GEOGRAPHIC INFORMATION SYSTEMS

IDRISI

ILWIS

ARC/

INFO

GIS SOFTWARE PEOPLE

POLICY AND

PROCEDURES

FOR

RESOURCE

MANAGEMENT

DATA HARDWARE

GIS Definition

Many expert used GIS for his own demand and that is

the reason that they define GIS in that context.

Aronoff (1989) gives a general description of GIS as

“any manual or computer-based set of procedures

used to store and manipulate geographically-

referenced data.”

More specifically, Aronoff (1989) defines GIS as "a

computer-based system that provides four sets of

capabilities to handle georeferenced data: i) data input

ii) data management (data storage and retrieval)

iii) manipulation and analysis iv) data output.”

Cower (1988) defines GIS as “a decision support

system involving the integration of spatially

referenced data in a problem solving environment”.

• A set of tools for storing, retrieving and

displaying spatial data from real world for

particular set of purposes (Burrongh 1986)

• It is automated systems for the capture, storage

retrieval, analysis and displaying of spatial data

(Clarke,1995).

• An information system that is designed to work

with data reference by geographic coordinate

Stave & Esles, 1990).

• It is information technology which store, analyses

and display both special and non spatial data

(Parker 1988)

–

HOW GIS WORKS

Thematic

object

selection

Real world

Maps

-Analysis

GIS operations

Cartographic

processing

.- Generalization

- Symbolization

Geology

Hydrology

Soil

Attribute tables

Decision makers

Statistical tables

GPS

Satellite images

Aerial

photograp

hs

Point

Area

Line

Field Survey

GIS

A computer-based

system capable of

holding and using

data describing places

on the earth’s surface

The real world

consists of many

geographies which

can be represented as

a number of related

data layers.

Hydrology

Landuse Districts

Topography

Soils

GIS IS NOT A DECISION MAKING TOOL

GIS IS SUPPORTING TOOL FOR DECISION MAKERS

Topographic

REAL-WORLD

Contour lines

Parcels

MAPS AND SPATIAL DATA

WHY GIS GIS has its unique ability as it “assimilate data from different divergent sources into one data system either if it is spatial or non-spatial data”.

Due to advancement in technology, its functions are gradually changing from data collection and analysis to the promotion of visualization, incorporating a variety of existing data sources and new techniques such as simulation models, multimedia and video. These techniques have ensured that the data, and in particular geo-reference information, become more accessible to non-technical audiences.

Sharing & Transferring of information worldwide.

70% of the information includes some geographical facts in the decision-making process.

QUESTIONS A GIS CAN ANSWER

Location What is at...?

What exists at a particular location. No of people

effected by Earthquake, number of hospitalised

population, EQ intensity & reasons etc.

Condition Where is it...?

Instead of identifying what exists at a given location,

one may wish to find location(s) where certain

conditions are satisfied (e.g., where the specific

earthquake has occurred, which areas has suffered

by the EQ etc.

Kisakhwani Bazar, Peshawar

Who owns the land at Kisakhwani Bazar, and its

assessment

Owner: Ali

Area: 255.2 sq.m.

Land use: residential

Assessment: Rs. 5000000

Trends What has changed since...?

The third question might involve both of the first two

and seeks to find the differences (e.g., in land use,

forestation or elevation) within an area over time.

Patterns What spatial pattern exists...?

The distribution of landslides & Why it is mostly

occurring on steep slopes (Or) Urban areas

distribution, specific cropping pattern.

Modelling What if...?

“What if..” questions are posed to determine what

happens, for example, if a new road is added to a

network or if a toxic substance seeps into the local

groundwater supply. Answering this type of question

requires both geographic and other information (as

well as specific models).

COMPONENTS OF GIS

Several components are involved in GIS technology.

Hardware

A computer and the associated accessories are essential for

handling spatial data in GIS. These devices are collectively

known as hardware like scanners, CPUs, Digitizers,

Workstations & plotters etc.

Software

Software refers to the programmes that run on computers;

these include programmes to manage the computer and to

perform specific functions. For example, DBMS, Corel draw,

ILWIS, Arc/view, Mapinfow, ERDAS Imagine, IDRISI and

Arc/info are specialised software programmes designed to

perform certain tasks. Continued………

Database A central theme to GIS is the database. A GIS database deals

with spatial data. GIS facilitate integration of spatial and

attribute data and this makes GIS unique in contrast to other

database systems. The beauty of GIS technology lies in the

ability to assimilate divergent sources of data and analyse them.

Human Input (live ware) People who work with GIS form the most important component.

GIS constitute truly a interdisciplinary field and require varied

backgrounds of expertise, depending upon the applications. In

addition, for technical management, a Hardware Specialist,

System Administrator, and Database Manager are required for

corporating the GIS set-up.

Policy and Procedures A methodology is must to derive the results users need.

Basically, this includes spatial analysis for the particular

application. By and large, this depends upon the institutional

framework and its interest in exploiting GIS technology for

decision-making

GIS Technology

GIS GIS borrows from other

software technology:

Relational

Database

Relational Database

Management Systems CAD

Graphics

Computer Assisted

Design and Graphics

Software

Statistical Analysis

Statistical Analysis

and Reporting

Packages

SPATIAL OPERATIONS Many computer programmes can handle geographic data such as those

described below.

Spreadsheets (e.g., EXCEL, Lotus). A spreadsheet can be thought of as a

large imaginary piece of electronic paper that can contain information in rows

and columns, which is used for all sorts of (mathematical) operations for

producing graphs. Spreadsheets are often used in combination with GIS.

Database Management Systems (e.g., Oracle, dBase, Access). A

Database Management System (DBMS) is a set of programmes which is a

collection of information about things and their relationships to each other

and which maintain and manipulate data in a database. A DBMS only

handles "attribute data" and cannot handle maps. It generally forms an

integrated part of GIS.

Computer Aided Design (e.g., AutoCad). CAD systems are for capturing

and manipulating drawings. Point, line, and polygon objects are stored in

vector format. A CAD system is like a part of a vector GIS. CAD software is

highly developed and has very good display capabilities, but, on its own, it is

neither designed to carry out spatial operations nor use raster data types.

Cartographic packages (e.g., Aldus Freehand, CarthoGraphix, ACE).

Cartographic packages or desktop mapping systems are for selective search

and display of information from spatial databases and for the production of

high quality output maps which meet cartographic standards. In this sense,

they form a useful addition to GIS, since the output facilities of most GIS are

still unsatisfactory.

Photogrammetrical software (e.g., DMS). Photogrammetrical packages

are designed to take point sample data (mostly of terrain elevations) from

aerial photographs, satellite images, and GPS (global positioning systems)

data, and then produce digital elevation models (DEM) and contour maps.

They form an important input source for GIS.

Image Processing Software (e.g., ERDAS imagine, ILWIS). Image

processing software is designed to handle satellite images, or scanned aerial

photographs. The information from such images can be extracted by several

kinds of image enhancement techniques and classification methods. Output

maps from image processing software often form the input into GIS. These

software packages are not considered to be GIS. The difference between

GIS and other software using geographic data is that only GIS permit spatial

operations on the data.

GEOGRAPHIC DATA

Spatial and Non-Spatial data

There are two important components of

geographic database: its geographic position

and its attributes or properties. In other

words, spatial data (where is it?) and

attribute data (what is it?)

•Analogue Data: A physical product displaying information visually on paper like maps, aerial photos, imageries, tabular data and written report etc.

•Digital Data: Information derived from computer

Geographic Data

SPATIAL DATA

City blocks Land use

001 Institutional

002 Commercial

003 Commercial

004 Residential

005 Residential

006 Residential

007 Industrial

008 Residential

009 Industrial

010 Industrial

011 Residential

012 Industrial

013 Residential

014 Residential

015 Residential

Map: City blocks

NON-SPATIAL DATA

SPATIAL AND NON-SPATIAL DATA

GIS - Links Data Sets

• GIS software links the location

data and the attribute data:

GIS software can answer

questions about our world:

What provinces border

N-W.F.P?

Spatial Questions:

What provinces have more

than 1.5 million people?

Attribute Questions:

GIS - Analysis

Base Map Data

GIS - Layers

• GIS contains many layers of

information:

Elevation

Surface Geology

These are just a few of

the kinds of layers a

GIS can contain:

GIS - Analysis

• GIS can analyze

data in many ways:

Maps model the real world with points, lines, and polygons. Symbols and labels

describe the descriptive information about the geographic features.

Points Points define the discrete locations of geographic features which are too small to

illustrate as lines or polygons such as well or telephone poles. Points can be used

to illustrate the locations of mountain peak or discrete elevation points.

Lines Lines represent the linear features of geographic object too narrow to illustrate as

polygons, such as streets and streams that have length but no area. Moreover,

contour lines are represented as the lines

By using different symbols and labels, descriptive information of linear features are

illustrated. For example: Roads are drawn with various line widths and patterns and

colors to represent different road types, e.g., highway as wide solid red colour line,

blue lines are used to illustrate the streams. The symbol can be used to

illustrate the railway.

City streets are labeled with names and often address ranges.

Basic types of spatial Data

Polygons Polygons are closed features that represent the shape and location of

homogeneous features such as landuse, forest types. Tone of the colour

can be applied to illustrate the density of population, green color can be

used to represent vegetation and blue colour can be used to illustrate

lake.

Surfaces A surface represents the elevation, presence or absence of something for

every point on the piece of earth. The elevation models are best examples

to illustrate as the surfaces.

Surfaces are typically represented on the maps as the series of isolines.

Elevation contours, rainfall, temperature can be represented as the

surface of isolines.

Surfaces can be represented as the Raster Elevation Model and Vector

Elevation Model.

Geometry of Spatial Data

Point Line

Area surface

Vector Graphics:

•Images are built-up from points, lines(segments) and areas

(Polygons).

•Each defined by pair of X-Y co-ordinates.

•Preparing a map by digitization is converted into vector data in computer.

Raster Graphics:

•Images are built-up from cells which is called as Pixels.

•In raster graphics, the smaller the area of land that each cell

represents, the higher the resolution of the data and higher the

spatial accuracy, ultimately the larger the files needed to store

the data.

REPRESENTATION OF GEOGRAPHIC DATA

SPATIAL DATA INPUT

X

Y

Scanning (automatic digitizing)

Editing Improving

Vectorizing

Apply attributes

X

Y

Manual digitizing

Raster model

Vector model

Sensor

Improving

Apply attributes

Digital Landscape

Model

APPLICATION OF GIS Canada was the pioneer in development of GIS as a result of innovations dating back to the early 1960s. Much of the credit goes to Roger Tomilson for the early development of GIS. Although the field of GIS has been around for the last 25 years the real potentials have become apparent only since the late 1980s. Afterwards widely used in USA, Canada & Western Europe.

Some typical examples of GIS applications are;

land-use planning and management e.g. Cadestral mapping,

Urban growth, Landuse changes etc. S.O.P, SUPARCO, P.D.A, C.D.A, P.E & D)

oil & mineral exploration (O.G.D.C, Oil companies, P.G.S)

environmental impact studies

management of water resources (IIMI, AKRSP, WAPDA)

natural hazard mapping (FFC, NESPAK)

forestry and wildlife management (FMC, PFI, AKRSP)

soil degradation studies (Soil survey of Pakistan)

monitoring desertification

agricultural development

socio-economic survey and mapping (S.O.P & Primary

education project in NWFP, Baluchistan, Sind, N.As & A.K.)

Environmental

• What are

the effects

of Global

Warming?

Land cover and temperature relationships are

made clear when the data are seen at once

using Geotechnology.

Park Management

• Will the new

building spoil

the Park

Scenery?

Park planners use Geotechnology to

determine if a new Visitor Centre can be seen

from the peak.

Agriculture

• How can I

improve food

production?

Geotechnology is used in

making crop management

decisions to maximize yields

and minimize fertilizer input.

Public Utilities

• Is it safe to

dig here?

A proposed excavation, identified by

address, is compared to pipelines in the area

using Geotechnology.

Health Care

• What

Communities

are at risk

from Disease?

Geotechnology identifies

communities at risk of River

Blindness and helps determine

the impact of treatment.

Emergency 999

• What is the

fastest route

to the

Hospital?

Geotechnology can choose the

fastest route to a hospital. The

GIS can take into account

traffic and other impediments.

Real Estate

• Where is my

Dream

Home?

With Geotechnology, an agent can

show a map of a neighborhood and a

picture or video of the actual

properties.

Marketing

• How can I

optimize my

Marketing

Campaign?

Geotechnology can query a database and

identify only those areas with the highest

household income within a specified distance

of a store.

THANK YOU