1. Lecture 07: Data Representation (V)
Topics
3. Data Models
3.3 Spatial data models
3.3.1 Raster Data Models
3.3.2 Vector Data Models
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
Chapter 3 in Burrough and McDonnell (1998), pp

2. Lecture 07: Data Representation (V)
3. 3 Spatial Data Models:
3.3.2 Vector data models:
A. Vector representation
The basic concept
(The Vector Representation Figure)
The representation of point, linear and area features
(The point, line, area in vector figure)

3. B. Terminology
Vertex
Node
Arc
Polygon
Label point
C. Spatial Topology
Spatial relationships of the basic geometric elements

4. D. Types of models
1) Entity by Entity (Spaghetti) Model
a) definition:
b) Versions of spaghetti models:
(1) Simple lists
(The simple lists figure)
(2) Point directory
(The point directory figure)
c) A comparison of spaghetti models
(The Spaghetti comparison figure)

5. E. Summary:
(1) Geographic features are treated as individual objects
The spatial boundary is explicitly coded
(2) No relationships among objects
Spatial topology among features are not explicitly coded

6. Questions
1. How does a vector data model represent spatial data? How does
it represent a point feature, a linear feature, and an area feature?
2. What are the advantages and disadvantages of the vector data
model?
3. What is an arc and what is a node? Can any point be a node?
what is the difference between arc and a polyline (a line made
of multiple straight segments)?
4. How are the three basic geometric elements are used to capture
spatial topology in a topological data model?
5. What is the main difference the simple list data model and the
point directory data model? Why don’t we consider them to be
topological data models?