1. Spatial Databases - Introduction
Spring, 2018
Ki-Joune Li

2. Spatial Databases What are on these images ? How to represent, store,
analyze, and
retrieve these data

3. What are on these images?
These include
Pixels
Objects
Buildings, Roads, Symbols, etc
Terrain
Height Data
Non-Spatial Data
Name of Roads, Levels of Buildings, Capacity of Bridge, etc
Relationship Between Objects
Goal of Spatial Databases
Spatial databases are for representing, storing and retrieve useful information from these data

4. Properties and Challenges
Characteristics of Spatial Databases
Spatial Data: Very Large Amount of Data
Example : more than 200 peta bytes for EOS Project
Very complicated
Major Challenges
How to represent sophisticated data: Representation
How to store and manage a large amount of data: Management

5. Issue I: Modeling Example What is Modeling? (cf. Schema Design)
Building Spatial DB about Pusan City
What is Modeling? (cf. Schema Design)
Modeling is much more important than schema design
Computer World
Real World

6. Issue II: Management System
How to Handle Large Volume of Data
Cost for Storage Media
Not very important and negligible
Processing Time
I/O time
How to reduce disk i/o time ?
DBMS Issue

7. Three Level Schema of Databases
Applications
External level (schema)
Logical (or Conceptual) Representation
Conceptual level (schema)
Independence
Physical Representation
Physical level (schema)

8. Spatial Databases ? Spatial Databases ? What are spatial properties ?
Databases for spatial phenomena
Spatial phenomena ?
Phenomena with spatial properties
Spatial properties ?
What are spatial properties ?
Example
Distance, Surface, Position (Coordinates)
Adjacency, Connectivity

9. Space Space What are spatial properties ?
Spatial extents (Area) where things are located or events happen
Space is given with spatial properties
What are spatial properties ?
Example
Distance, Surface,
Spatial Reference System: how to specify a position (Coordinates)
Adjacency, Connectivity

10. Spatial Properties: Space
Depending on the Type of Space
Euclidean Space
Flat space represented by Rn coordinate systems
Point p is represented as an n-ary tuple (x1,x2, …, xn)
Road Network Space,
Terrain Space,
Indoor Space

11. Euclidean Space vs. Constraint Space
Distance is determined by the straight line connecting two points
Constrained Space
Constraint on the straight line
Distance is the length of shortest path detouring constraints
Examples of Constraint
Road Network
Indoor
Terrain

12. Example: Indoor Space Real distance Elevator Stairs p W.C. 405 401
Emergency Bell A
404
406
Emergency Bell B

13. 2-D space and 3-D space 3-D (cf. 2-D) More information
Large amount of data
Example
Rectangle: 4 vertices, 4 edges, and 1 face
Cube: 8 vertices, 12 edges, and 6 faces
Complicated geometric processing
Overlapping of two polygons
Overlapping of two polyhedrons

14. 2.5-D space 2.5-D space (cf. 3-D space) Field and 2.5-D
3-D space: Solid Modeling
2.5-D space
Only one height value at any given point: f (x, y)=h
Field and 2.5-D
Field: Terrain, Temperature distribution, etc..
2.5-dimensional representation: Field Representation

15. Spatio-Temporal Model
Spatial Model
Stationary objects or phenomena
Every object on the earth is moving!
Spatio-Temporal Model
Object changing its location or shape according to time
Discrete change
Example: Change of administrative boundary
Continuous change
Example: Moving Objects, Meteorological Lines, Pollution Areas

16. Topological and Geometric Properties
Geometry: Geo + Metry
Geo: Earth, Space
Metry
meter, metric, etc..
something to measure
Geo+Metry
Something to measure in space
Quantitative
m, m2, etc..
Topology
Relationship between Spatial Objects
Qualitative
adjacent, inside, left, right

17. Spatial Database Building Procedure
Comparison with Software Life Cycle
Requirement Analysis
Requirement Analysis
Functional Specification
Modeling
Design
Schema Design
Development Environments
DB Environments
Coding
Data Collection and Input
Test
Quality Control
Maintenance
Management and Retrieval

18. Spatial Database Building Procedure
Requirement Analysis
Scope of databases: depends on applications
Data Items, Attributes, Accuracy, etc..
Use-Case Diagram
Current State: As it is
As it must be

19. Spatial Database Building Procedure
Data Modeling
Understanding the real world and application
A very small piece of the real world
According to viewpoint
Determined by applications
Drawing what you have understood in formal method
Example. UML
4 steps
Requirement Analysis
Entity and Granularity
Attributes
Relationships

20. Spatial Database Building Procedure
Data Collection
Legacy System and Databases
Interoperability and Standard Issue
Data Generalization
Metadata
Data Input
Relies on Manual work
Automatization

21. Spatial Database Building Procedure
Quality Control
Check the correctness of data
Maintenance
Periodic Backup
Updates
Equivalent to 30% of the total amount of data
Determine the quality of DB