Introduction to gis

Muhammad Haris Lecturer GIS Center PUCIT

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Introduction to GIS


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Topics:

• GIS for a Beginner

• GIS Around Us

• Major Application Areas

• Maps & GIS Softwares


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Agenda:


• GIS around us

• Major Application areas


What is Geography

• Geo – Earth • Graphy – Measurement• Geography hence is measurements and calculation

related to Earth

• Geography is divided into two main branches: – Human geography – Physical geography


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Physical geography


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Human geography


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Geography in Final Words

Geography is the science that studies the lands, features, inhabitants, and

phenomena of Earth

Or SimplyGeography is the study of any thing

related to Earth


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Informally

GIS(Geographical Information System)

=

G + I S (Geography) + (Information System)

Geography is the science that studies the lands, features, inhabitants, and phenomena of Earth

Information System – A way of managing and manipulating the information digitally (using computers and digital devices)

1st Definition of GIS(Beginner Level)


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People normally don’t

realize that how

important Geographic

Information is.


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Estimates are that 80% of all data has a spatial component

• Cellular Phone location

• ID cards

• Telephone Directories

• Registration

• Your favorite restaurant, park , shopping mall address.


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GIS stands for Geographical Information System The “bookish” definition:

GIS is a system for

capturing, storing,

analyzing, managing

data that is associated to the earth w.r.t location


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Spatial = Geographical = Locational

Very Important !Very Important !


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GIS = Spatial + AttributeGIS = Spatial + Attribute

A GISA GIS links locational/spatial and attribute(non-locational) information and enables a person to visualize patterns, relationships, and trends easily and efficiently

Helps identify patterns not easily visible on paper map.

2nd Definition of GIS(Intermediate Level)


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GIS – Finding Patterns

To explore highway accidents, we might first make a map of where each accident occurred.

We might use one color to locate those accidents that occur at night and a second color for those that occur during the day, and then we might see a more complex pattern.


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A


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But how exactly

GIS works?


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GIS = Overlaid layers

3rd Definition of GIS(Advance Level)


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Example


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Raster -- GridRaster -- Grid• “Pixels”• Each Pixel has a value• Satellite images and aerial

photos are in this format

Vector -- LinearVector -- Linear• Points, lines, and polygons• Each feature stores

attributes

Spatial Data Formats


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Representation of Lines

Raster

Vector


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VECTOR• Advantages:

– Accurate calculations – Better visualization due to more detail – Compact data structure => small storage requirements

• Disadvantages: – Complex data structures

– Cannot handle remotely sensed data


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RASTER• Advantages:

– Simple data structures – Can display and manipulate remotely sensed data

• Disadvantages: – Inaccurate graphics and area calculations – Blocky appearance with loss of detail as we zoom into

the data– Large storage requirements


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Example


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Rivers LayerRivers Layer Lakes LayerLakes Layer Capitals LayerCapitals Layer

Roads LayerRoads Layer States LayerStates Layer

5 Data Layers


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The GIS process


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The GIS process

CaptureStore

Visualize

AnalyzeGet Result


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Agenda:


• GIS Around Us




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Google Maps


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Google Earth


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Map Maker


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Google Maps Street View


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WikiMapia


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Agenda:• GIS for a Beginner

• GIS around us




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Animal Tracking Tracking endangered animals using radio transmitters


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3D Modeling for Urban Planning


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Determining Location for Service Areas Example: Gourmet Bakery


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Property Locator Internet Application


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Centure 21 (century21.ca)

Selling, Renting, Purchasing houses


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Emergency RoutingFind Nearest Hospital

Find Shortest path to it


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US Flights Around the World


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Agenda:• GIS for a Beginner

• GIS around us




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Plot Level Map of DHA


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General Overview Map of DHA


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Satellite Map/Image of DHA (from Google Earth)


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Lets Revise

– GIS is G + IS – GIS is Attribute + Spatial– GIS is Layers– GIS is about finding patterns, static maps won’t easily– Spatial Data Formats (Raster , Vector)– GIS Applications areas (3D Models, Emergency routing, etc. )

– GIS around us – Goolge Earth & Maps, Wikimapia

Assignment

2 GIS Applications

http://googlemapsmania.blogspot.com/

http://www.proxywebsite.org/


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http://googlemapsmania.blogspot.com/

http://www.proxywebsite.org/


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Where GIS is being used


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Raster Data’s Resolution

1.Spatial resolution

2.Spectral resolution

3.Radiometric resolution


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Spatial ResolutionThe term resolution is the pixel count in digital imaging

Higher the number of pixels, higher is the

spatial resolution.

• Spatial Resolution is the size of areas represented by each pixel in a digital photo

• Google Earth Images has a spatial resolution of 1 meter per pixel


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Spectral ResolutionIt is the range of wavelengths that an imaging system (satellite)can detect

Higher the wavelength range, higher is the spectral resolution.

Spectral resolution can also be defined as the number of frequency bands recorded.

Higher the number of Bands Higher the spectral resolution


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Radiometric ResolutionRadiometric resolution determines how finely a system can represent intensity, and is usually expressed as a number of levels or number of bits.

Important:For example a Raster Data that use 16 bits to store intensity for a single pixel has more level of intensity than a raster data that uses 8 bits


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GIS Softwares


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GIS Softwares

• MapGuide, GeoTools, uDig, MapServer

• ESRI leads in the GIS field• Pioneers in GIS,

• The 5 Largest Privately Held Software Company in the World

• Extensive range of GIS software and Research material

• Their flagship product ArcGIS leads in the GIS software domain

Introduction to gis

Documents

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