1. Lecture 08: Data Representation (VI)
Topics
3. Data Models
3.3 Spatial data models
3.3.2 Vector Data Models II
Readings on the topics
Chapter 8 in the text, pp
Chapter 6 in Aronoff’s (1993), pp
Other readings
Chapter 3 in Bonham-Carter’s (1994), pp

2. Lecture 07: Data Representation (V)
3. 3 Spatial Data Models:
3.3.2 Vector data models II:
D. Types of Vector Data Models
1) Spaghetti (Entity by Entity) Models
2) Topological Data Models
(1) Definition
(The topological data model figure)
(2) Versions of Topological Models
a) GBF/DIME data model (US Census Bureau)
(The GBF/DIME figure)
b) DLG (USGS)
(The DLG Figure)

3. (3) Evaluation of Topological Data Models:
(a) Topologic is explicitly encoded
(b) Special instances can be encoded
(c) Very compact
(D) Complex, difficult to construct

4. Questions
1. What is a topologic data model? What is a topological triangle?
2. What are the advantages and disadvantages of a topological
data model?
3. You should be able to code a simple map using a topological
model with the needed topology given in a topological triangle.
4. Describe the DIME data model of US. Census Bureau and
describe the DLG data model from USGS.