This document provides an introduction to geographic information systems (GIS). It defines GIS as a computer system for capturing, storing, analyzing and displaying spatially-referenced data. A GIS integrates database operations with maps in digital form and allows users to create interactive queries, analyze spatial information, edit maps and present results. The document outlines key components of a GIS including data, databases, processing capabilities, hardware and communications. It also discusses the importance of location in problem-solving and decision making as well as the history and business applications of GIS technology.

1. Introduction to GIS
BY : EHSAN HAMZEI - 810392121

2. GIS ?
 Everyone has their own favorite definition of a GIS, and there are many to
choose from.
 Ex:
 A container of maps in digital form (The general public)
 A mechanized inventory of geographically distributed features and
facilities. (Utility managers, transportation officials, resource managers)
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3. GIS ?
 A geographic information system (GIS) is a computer-based information
system that enables capture, modelling, manipulation, retrieval, analysis
and presentation of geographically referenced data.
 Two of the most important technologies underlying GIS are database
systems and computer graphics.
 One way of understanding GIS is to look at its application.
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4. Schematic of a GIS 3

5. Schematic of a GIS 4
 At the heart of any GIS is the database. The data that are held in the
database are given context and meaning by the application domain(s) and
then take on an informational value.
 Data are only useful when they are part of a structure of interrelationships
that forms the context of the data. Such a context is partly provided by the
data model.

6. GIS Vs. Traditional IS 5
 Most traditional IS, require only limited presentational forms, usually based
around tables of data, numerical computation and textual commentary.
 But in GIS, the spatial nature of the information allows a whole new range
of possibilities, including cartographic forms and visualization techniques.

7. Why Does GIS Matter?
 Almost everything that happens, happens somewhere. Knowing where
something happens can be critically important.
 Problems that involve an aspect of location, either in the information used
to solve them or in the solutions themselves, are termed geographic
problems. Ex (where to locate new Clinic)
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8. Classification of Geographic Problems
 Based On:
Scale
Purpose
Time Scale
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9. Classification of Geographic Problems
 1- Scale or level of geographic detail is an essential property of any GIS
project.
 2- Some problems are strictly practical in nature, But others are better
characterized as driven by human curiosity. The Difference Between them is
Purpose! (Normative Vs. Positive)
 3- Time Scale for different Problem, Widely changed !
 (Ex: Geomorphologic Problem Vs. Traffic Problems)
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10. Why GIS is Special?
 1- Multidimensional
 2- Voluminous
 3- Time Consuming to Analyze
 4- Complex and Expensive (Update)
 5- Multi Resolution representation
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11. Geospatial Vs. Geographic
 Geographic : Geographic refers to the Earth surface and near surface
 Spatial : Spatial refers to any space not only the space of the Earth’s
surface;
 Geospatial : implying a subset of spatial applied specifically to the Earth’s
surface and near surface.
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12. Decision-making support
infrastructure
Wisdom
Knowledge
Evidence
Information
Data
Ease of sharing - Impossible
Ease of sharing - Easy
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13. Knowledge Vs. Information
 3 Important Difference:
 1- Knowledge entails a knower
 2- Knowledge is harder to detach from the knower than information
 3- Knowledge requires much more assimilation – we digest it rather than
hold it
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14. Knowledge
 2 Type:
 1- codified
 2- tacit
 Knowledge about how the world works is more valuable than knowledge
about how it looks, because such knowledge can be used to predict.
(Idiographic Vs. Nomothetic)
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15. History of GIS
 The first GIS was the Canada Geographic Information System, designed in
the mid-1960s
 ODYSSEY GIS of the late 1970s
 The first automated cartography developments occurred in the 1960s
 The modern history of GIS dates from the early 1980s, when the price of
sufficiently powerful computers fell below a critical threshold
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16. Anatomy of a GIS 15

17. Data 16
 1- Correctness and accuracy
 2- Timeliness, relevance and cost
 3- Usability and accessibility

18. Database 17
 For a database to be useful it must be:
 1- Secure
 2- Reliable
 3- consistent
 4- Technology proof

19. Processing Requirement 18
 1- Geometric and topological analyses, Ex: Proximity
 2- Fields, surfaces and layers, Ex: Aspect
 3- Network analysis, Ex: Shortest path

20. Hardware 19
 major functional components of a computer

21. Hardware 20
 Input Devices :

22. Communications 21
 Only in the ideal world is it the case that the signal transmitted is equal to
the signal received, In the real world degradations occur:
 1- Attenuation
 2- Delay
 3- Noise

23. Communications 22
 Networks:
 1- wide-area network (WAN): a network of computers spread over a large
area.
 2- A local-area network (LAN): a network of computers spread over a small
area.

24. Communications 23
 Client-server computing:
 Client-server computing is a form of distributed computing in which some
stations act as servers and some as clients.
 A server holds data and services available for transmission to other
stations, clients, in the network.

25. Communications 24
 Type of Messages in Client-Server Architecture:
 requests from client to server.
 replies from server to client.
 events from server to client.
 errors.

26. The Business of a GIS 25
 1- Software Industry
 2- Data Industry
 3- GI Service Industry
 4- Publishing Industry
 5- GIS Education

27. Thanks 26