basic concept of geographic data,GIS and its component,data acquisition ,raster, vector formats,spatial data,topology and data model data output ,GIS applications

1. Introduction to GIS
Lecture 1

2. Introduction to GIS
• What is GIS?
G ?
I ?
S?
Geographical
Information
System

3. What is Geography?
Definition:
Geography is the study of the world's environment
and man's interaction within the environment.”
Geography has two “strands” or parts:
1.PHYSICAL:
The study of the earth's natural features, such as mountains,
rivers, soil, vegetation, and weather
2. HUMAN: (Cultural)
The study of human cultures and man made features.
“All kinds of resources are used to study geography, but the
most common are MAPS.”

4. Why Geography is important?
• Why are we more interested in spatial data
today than 100 years ago?
Reference: Bolastad, 2008

5. Why GIS is Important?
• What is Where? :
– Query information to find location
Or
• Where is what?
– Obtain information from a location
• Applied geography, in the form of maps and spatial
information, has served discovery, planning,
cooperation, and conflict for at least the past 3,000
years (Bolstad)
• Impact of spatial information on our lives?

6. Type …….
Species …….
Heights …….
Use …….
O O
X South, Y West
Location Information:
Where is it?
Attribute Information: What
is it?
There are two ways of explaining any
element/object on the Earth
GIS can tell us Where and What

7. GIS is about Geospatial
Information
• Geography/Geospatial: Information about
places on earth
• Not only Where and What but time is also
important
What is Where, When?

8. S in GIS?
• S as in System
– Technology (for acquiring and managing GIS data)
• S as in Science
– Concept behind the technology. Theoretical foundation on
which GISystems are based
• S as in Studies
– Societal context (social, legal, and ethical issues related to
GIS application)

9. Simpler Definitions
• A GIS helps us gather and use spatial data
(Bolstad)
• A computer system which can hold and use
data describing places on the earth's surface.

10. GIS...
A GIS is not simply a computer system
for making pretty maps. More
importantly a GIS...
• ... is an analysis tool
• ... links spatial data with geographic
information about a particular feature on a
map
• ... can use the stored attributes to compute
new information about map features

11. A more Comprehensive Definition
• A GIS is a computer-based system to aid in
the collection, maintenance, storage,
analysis, output, and distribution of spatial
data and information.

12. • A powerful set of tools for collecting, storing, retrieving at
will, transforming and displaying spatial data from the real
world. (Burrough, 1986)
• Any manual or computer based set of procedures used to
store and manipulate geographically referenced data.
(Aronoff 1989)
Some other popular definitions of GIS

13. • A decision support system involving the integration of
spatially referenced data in a problem solving
environment. (Cowen 1988)
how to deal with stuff in space.
• Systems that know
(Herrington 1998)
Some other popular definitions of GIS

14. Conventional Ways to Store Data
DATABASES
•A Database comprises
of tables having fields
with specific data
structure.
•The tables are linked
with each other through
various common fields.

15. Conventional Ways to Store Data
MAPS
•Map can be defined as “A Facility
for displaying interpretation of
geographic information on a flat
surface.”
•Location information describes the
position of a particular geographic
feature on earth's surface & provides
the basis for representing spatial
relationships between these
features.

16. Databases Vs Maps
Bad
Visual Interpretation
Bad
Searching
Very good
Searching
Very Good
Visual Interpretation
What? if link
together

17. Basic GIS Functions

18. Capture
Store
Query
Analyze
Display
Output
Collecting data using different data structures and
technologies – GPS, RS, Digitizing, etc.
Data stored in the form of databases, spatial files,
drawings, images, etc.
A GIS must provide utilities for finding specific
features based on their location or attribute values
A GIS must have the ability to answer questions
regarding the interaction of spatial relationships
between multiple datasets
There must be tools for visualizing the spatial
information in the form of maps
Results of display should be able to be output in a
variety of formats
Basic GIS Functions

19. GIS Functions
Data Capturing

20. GIS Functions
Storing Data
 Tables

21. GIS Functions
Spatial Query
Query: Select Florida on map

22. GIS Functions
Spatial Analysis

23. GIS Functions
Display

24. GIS Functions
Output

25. GIS Functions
Output
- Maps (Topographic,
Statistical, 3D, Contour etc)
- Atlases
- Reports (Write-ups etc)
- Charts, Graphs
Hard Copy
- General Applications
- Special Applications
- Customized Applications
- Web-based Applications
- Mobile Applications
- Multimedia
- Product Presentation
Soft Copy

26. GIS Key Components
1. GIS hardware
2. GIS software
3. GIS data (maps, images, database, etc.)
4. People
5. Methods

27. GIS Components
Hardware Hardware is the computer system on which software operates

28. GIS Components
Hardware
Reference: Bolstad

29. • GIS software provides the functions and
tools to store, analyze, and display and
disseminate spatial data and information
• Many public domain commercially
available software packages in the market
• ESRI (Environmental Systems Research
Institute) line of products a good example
(including ArcGIS)
GIS Components
Software

30. GIS Components
Software
Key components to GIS software:
1. An easy-to-use graphical user interface (GUI)
2. Tools for entering and manipulating geographic
information
3. Tools that support geographic query, analysis and
visualization
4. A database management system (DBMS)

31. Functions Commonly Provided by
GIS Software
Reference: Bolstad, 2008

32. GIS Components
GIS Data
Map + Database
• Virtual or digital maps (virtual representation of
world)
• Map = Spatial representation of features
• Database = Feature attributes
Data Sources
• Available through various sources like profit and
non-profit organizations, academic institutions,
government agencies

33. GIS Components
GIS Data
Flood Zones
Wetlands
Landcover
Electric Lines
Gas Pipe Lines
Soils
Land Ownership
Transportation
Surface Waters
Boundaries
Geodetic Control
Elevation
Satellite Imagery
GIS Combines Data from Many Sources

34. GIS Component
Data Format

35. GIS Components
GIS Data

36. Attribute Type
GIS Data
• Nominal: descriptive information associated with a
spatial entity
– country name: Bangladesh, Pakistan, India, ….
– highway class: Major highway, local streets, ….
– crop type: Maize, cotton, wheat, ….
– etc
• Ordinal: rank order or scale by their values. Such
as small, medium, large (soil erosion class, drainage
class…). Does not infer a specific scale.
• Interval/ratio: numeric items where both order and
absolute difference in magnitude. Real numbers
usually on a linear scale (area, length, weight, height
etc.)

37. GIS Components
Peoples
• GIS personnel may include
– GIS technologist to design and maintain the
system
– GIS users (analyst, manager, etc.)

38. Other GIS Components
• Supporting institution
• Protocol for use

39. Some Advantages of GIS
• Automation of procedures involving geographic
data (map making, calculation of area, slope,
etc., and planning and management activities)
• Integration of data from different independent
domains
• Visual Interpretation of spatial data depending
on various criteria
• Perform Spatial Queries and complex Spatial
Modeling (what if scenarios)
• More

40. • Geo-spatial data are better maintained in a standard
format
• Revision and updating are easier
• Easier to search, analyze and represent
• More value added as well as thematic product
• Geo-spatial data can be shared and exchanged freely
• Working productivity is improved and more efficient
• Time and money are saved
• Better decisions in short span of time
GIS Benefits