GIS-Introduction

1. Geol 465- Intro to GIS
Geographic Information Systems

2. Evaluation
• Grades are based on two exams and
completion of assignments in the lab
part of the class
• Midterm Exam is 22% of grade each
• Final exam is 44% of grade
• Labs are 34% of grade

3. Lab exercises
• Software and hardware needed to
complete lab exercises are available in
this room (SC3211)
• Files needed to complete the exercises
are available from the textbook, from me,
or from a wide range of online sources

4. What is GIS?
• A tool to be used by researchers
• System involves collected, tabulated, processed,
analyzed geographical data used to solve,
diagnose or prevent problems
• Maps are heavily utilized
– Not the only means of portraying information
– Differs from a CAD* system or a CAC‡ system
• Arguably more powerful due to ability to generate
DERIVATIVE data sets from pre-existing data
* Computer Aided Design
‡ Computer Aided Construction

5. Subsystems for GIS
• Data input and Preprocessing
– Transformation of spatial data types
• E.g., from topo lines to elevation data points
• Data storage and retrieval
• Data manipulation and analysis
– Modeling, simulations, estimates
• Lloyd expressway example
• Data reporting and display of information
– Tabular, graph-based, or map based

11. Information systems
Non-spatial Spatial
Management
systems
Nongeographic Geographic
Info Systems
CAD/CAM* LIS
Other
systems
*Computer Aided Manufacturing

12. Digital data
• Has benefits over analog (non-digital) data
– Photographic example
– Rectification- alignment to coordinate system
Unrectified
Rectified

13. Digital data
• Continuous data sets are not easily represented
– Example topographic map data
• Analog maps versus Digital elevation models

14. Topographic map grid

15. Same image as previous one, grid cells are shaded

16. Same image as previous two, just rotated to vertical

17. Georectified aerial and
satellite photographs

18. Overlaying vector based maps to create derivative maps
Color is
attribute
as is
alphabetic
designation

19. Layers of
geographic
information,
which in turn
can create
new layers
of data

21. Soils layer

22. Land Use Layer

23. Topographic
layer

24. Watershed boundaries
layers

25. Tiger file layer

26. Point specific layers
Weather stations Point source pollution