2. Topics:
• GIS for a Beginner
• GIS Around Us
• Major Application Areas
• Maps & GIS Softwares
Muhammad Haris 2
Lecturer GIS Center PUCIT
3. Agenda:
• GIS for a Beginner
• GIS around us
• Major Application areas
• Maps & GIS Softwares
Muhammad Haris 3
Lecturer GIS Center PUCIT
4. 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
Muhammad Haris 4
Lecturer GIS Center PUCIT
7. Geography in Final Words
Geography is the science that studies
the lands, features, inhabitants, and
phenomena of Earth
Or Simply
Geography is the study of any thing
related to Earth
Muhammad Haris 7
Lecturer GIS Center PUCIT
8. Informally 1st Definition of GIS
(Beginner Level)
GIS
(Geographical Information System)
=
G+IS
(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)
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Lecturer GIS Center PUCIT
9. People normally don’t
realize that how
important Geographic
Information is.
Muhammad Haris 9
Lecturer GIS Center PUCIT
10. 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.
Muhammad Haris 10
Lecturer GIS Center PUCIT
11. 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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Lecturer GIS Center PUCIT
12. Very Important !!
Very Important
Spatial = Geographical = Locational
Muhammad Haris 12
Lecturer GIS Center PUCIT
13. 2nd Definition of GIS
(Intermediate Level)
GIS = Spatial + Attribute
A 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.
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Lecturer GIS Center PUCIT
14. 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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Lecturer GIS Center PUCIT
16. But how exactly
GIS works?
Muhammad Haris 16
Lecturer GIS Center PUCIT
17. 3rd Definition of GIS
(Advance Level)
GIS = Overlaid layers
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Lecturer GIS Center PUCIT
18. Example
Muhammad Haris 18
Lecturer GIS Center PUCIT
19. Spatial Data Formats
Raster -- Grid
• “Pixels”
• Each Pixel has a value
• Satellite images and aerial
photos are in this format
Vector -- Linear
• Points, lines, and polygons
• Each feature stores
attributes
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Lecturer GIS Center PUCIT
20. Representation of
Lines
Raster
Vector
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Lecturer GIS Center PUCIT
21. 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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Lecturer GIS Center PUCIT
22. 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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Lecturer GIS Center PUCIT
23. Example
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Lecturer GIS Center PUCIT
24. 5 Data Layers
Rivers Layer Lakes Layer Capitals Layer
Roads Layer States Layer
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Lecturer GIS Center PUCIT
45. Satellite Map/Image of DHA (from Google Earth)
Muhammad Haris 45
Lecturer GIS Center PUCIT
46. 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
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Lecturer GIS Center PUCIT
48. Where GIS is being used
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Lecturer GIS Center PUCIT
49. Raster Data’s Resolution
1. Spatial resolution
2. Spectral resolution
3. Radiometric resolution
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Lecturer GIS Center PUCIT
50. Spatial Resolution
The 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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Lecturer GIS Center PUCIT
51. Spectral Resolution
It 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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Lecturer GIS Center PUCIT
52. Radiometric Resolution
Radiometric 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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Lecturer GIS Center PUCIT
53. GIS Softwares
Muhammad Haris 53
Lecturer GIS Center PUCIT
54. 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
Muhammad Haris 54
Lecturer GIS Center PUCIT
Hinweis der Redaktion
Geographic information systems (GIS) allow us to conduct spatial analysis faster, better, and cheaper now than in Dr. Snow’s day. He only had to compare two competing theories. What if he wanted to analyze all aspects of the victims’ lives. How close did they live to various factories? Where did they get their meats, fruits and vegetables, or breads? Where did they go to school, work, or church? What were their mattresses made of? How many people lived in their homes? What kind of wood did they burn for fires? What kind of oil did they use in their lamps? What materials were their clothes made out of? The list of possible questions is endless. Answering all those questions and determining if they were at all related to the cholera outbreak in a timely manner would have been an impossible task for Dr. Snow. With GIS we can.
There are two ways that the layers can be visualized on a map; as a vector or raster layer Raster layers are organized in a grid of identically sized cells. The top image is an example of a raster layer. The cells have a uniform length and width (square shaped) and are called “pixels.” Each cell has its own individual attribute data. Satellite images and aerial photos are types of raster layers where each cell displays what light wavelength is emitted or reflected from that location. The cells in a pure black and white photo represent whether light does emit or reflect from a cell’s location (white) or does not emit or reflect from the location (black). Examples of raster layers include temperature, elevation, and satellite imagery. Vector layers are represented as points, lines, or polygons. A vector layer cannot mix types together. One layer cannot have both points and polygons. The layer would have to be split into two separate layers; one for points and one for polygons. The bottom image is an example of at least three separate vector layers forming one image. Vector data is used when the features have specific locations and boundaries and the attribute data is uniform throughout the individual features. Examples of vector layers include bus stops (point), roads (line), and counties (polygon).
This slide shows five distinct, but related, data layers. The Capital layers is an example of a point vector layer. The Roads and Rivers layers are examples of line vector layers. The Lakes and States layers are examples of polygon vector layers.
When the five data layers from the previous slide are loaded into a digital map they combine into this one image. Each layer is still separate and can be turned on and off individually. The legend on the left side of the image shows the order of the images. The States layer is at the bottom of the image while the US Capitals layer is at the top. The layer order determines how the map draws the image with the top layers being drawn on top of the layers below it. If the States layer was moved to the top of the order it would cover the other layers and nothing else would be visible (except for the Great Lakes features of the Lakes layer) because it is being drawn on top of the other layers.