1. Review

2. What is GIS?
GIS is an information system that allows for capture, storage, retrieval, analysis and display of spatial data.
All of those definitions have some things in common:
-- computer, mapping, analysis, etc.
So in spite of this confusion about what it is, there are some key characteristics of a GIS we can identify.

3. Characteristics of GIS?
Computer
Hardware
Computer Software
People
Data
The 1st group of characteristics computer software.

4. Computer Hardware Computers Disk storage Digitizers and scanners
Printer and plotter output devices

5. Computer Software Location
ability to recognize and integrate locational information from a variety of sources
(spatial) - ability to recognize and integrate locational information from a variety of sources

6. Computer Software Attributes
ability to associate attribute information with geographic locations

7. Computer Software Manipulation/Analysis
Ability to manipulate or analyze the data to meet the needs of users.
Overlays
Buffers
Distance calculations
Within/adjacency operations

8. Data The geographic and attribute information itself
Remotely sensed data
GPS data
Census data
Road network
Elevation data
Climate data
Power line coverage
Hydrography
Key characteristics.
Data is a key characteristic to

9. Semantic Chaos Geographic Information / Data map data spatial data
locational data

10. People
People
People
users knowledgeable about geographic concepts and theory, GIS software, and data who can carry out the process

11. How Does GIS Work? Information System Chain of Operations Collecting
Data
Storing and Analyzing
Data
Using
Information
for
Decision Making

12. How Does GIS Work?
The first step of using a GIS is the collection of data
Most data collection requires some type of data transformation
Collecting
Data

13. Four Major Mapping Transformations
1. Entity to Object
real world entities to data
Take a real world object and put it into a database.
Location of a building
Location of people
Characteristics of an object

14. Four Major Mapping Transformations
2. Symbolization Transformation
map to data - digitizing data to map – mapping entities with locational information

15. Four Major Mapping Transformations
3. Object to Object
changes in data structure or scale
Change scale

16. Four Major Mapping Transformations
4. Map Base Transformations
mapping units (e.g. degrees, meters, feet)
projection
coordinate system
datum
Projection change

17. Algorithmic transformations in a GIS
Used for these transformations:
object to object
base map transformations
Geographic Data Transformation Algorithm=New Data
New
Data
Geographic
Data
Algorithm
An algorithm is simply a rule or set of procedures for solving a problem. GIS programmers code most of the algorithms we commonly use into GIS software. While many users of GIS are not algorithm programmers, the more you understand the fundamental concepts being carried out by algorithms, the better qualified you are as a user of the software.
If the program doesn’t do what you need, develop your own transformation algorithms and write computer programs to execute them (C, Avenue, AML Visual Basic, etc.

18. How Does GIS Work? The next step is to store the data in a database
Database organization is the key to a successful project
Storing and Analyzing
Data

19. Simple Database Example
Orange Co.
Processed
Unprocessed
Base Data
Derived Data
Satellite Images
Land Cover
Roads
Cities
Rates of Deforestation

20. How Does GIS Work? Once the database is complete, analysis can begin
Analysis also involves the use of some algorithms
Can be as simple as an overlay
Can be as complex as a hydrological model
Storing and Analyzing
Data

21. How Does GIS Work?
After analysis, the information is communicated, most often through a map
The information can then be used to make decisions
Using
Information
for
Decision Making

22. Chloropleth This potential exists for nearly all maps.
Source:

23. Dot Density
This potential exists for nearly all maps.

24. Cartogram 1995 2030 Change The Americas 775 1080 +39%
This potential exists for nearly all maps.
Change
The Americas %
Europe %
Africa %
Asia %
Source:

25. Next Class Basic Geodesy READINGS Heywood, Chapter 1 (by Sept 7)
Heywood, Chapter 2, pp. 20 – 34 (by Sept 12)