1. Introduction to GIS

2. Objectives Brief History of Maps Limitations of Maps
Introduction of the Computer
What is a GIS?
Decision-Making
Success of a GIS
The Data Set

3. Brief History of Maps History Greeks/Romans 18th Century
Scale – distance
Planimeters 1st used to measure area
Roman surveying instrument called a groma – used for measuring right angles to align streets N-S and E-W.
Planimeter used to measure areas of polygons.

4. The Babylonian clay tablet, the oldest world map known to us; Date: Sixth century BCE

5. Limitations Generalization Large area – several maps needed
Edge matching problems
Generalization
Edge Matching

6. Introduction of the Computer
Speed
Current georeferenced data
Integration of multiple data sets
Maps as snapshots of changing data
Iterative approach possible
$100 million IBM/Los Alamos Lab Supercomputer = Fastest Computer on Earth (1 trillion computations/second) in 2008
Chinese supercomputer even faster today in 2012 (2.45 pentaflops per second)
Maps showing anticyclone data changing through time.
Integration of multiple data sets.

7. Integration of multiple fire data sets.

8. What is a GIS?
A Geographic Information System is a computer-based system that provides the following 4 sets of capabilities handle georeferenced data:
1.    Input
2.    Data management (data storage and retrieval)
3.    Manipulation and analysis
4.    Output
GIS’s perform spatial search and overlay analyses as well as network analyses.

9. What is a GIS (cont.)?
Data Input – converts data from another existing form into one that can be used by the GIS.
Data Management – includes those functions needed to store and retrieve data from the database.
Data Manipulation and Analysis – these functions determine the information that can be generated by the GIS.
Data Output – may be in the form of maps, tables of values, graphics, or text in hard or soft copy.

10. Decision-Making Models Site selection planning process example
“right decision”

11. Vector vs. Raster Data Models

12. Success of a GIS depends on:
1.    The data set
2.    The data organization
3.    The model
4.    The criteria

14. The Data Set Must have DATA! Cost effective = use only what’s needed
Optimal quality – accuracy, precision, time, currency, completeness
As quality needs increase, so does cost (exponentially)

15. Georeferenced Data 2 components:
1)   the phenomenon being reported (i.e. the size, class, type, etc.);
2)   the spatial location of the phenomenon (i.e. the coordinates, address, etc.)
Represented as:
1)   Points;
2)   Lines; or
3)   Polygons

16. Collecting Georeferenced Data

17. Why Use a GIS? Digital = compact, fast Integration easier
Lower cost per unit
Iteration easier, faster
Currency maintained

18. Summary First maps were useful, but limited
Limitations include generalization, large area/size, edge matching issues
Introduction of the computer increased efficiency
GIS  data input, management, analysis, and output
Used for decision-making
Success depends on data set, data organization, model used, and criteria
Data set  access to data, quality, and cost are all important