Advanced archgis 2006 panda Lecture3.ppt

gis

1. GEOL 404/504 GEOL 404/504
Advanced GISAdvanced GIS
Sudhanshu Sekhar Panda, PhD
Lecturer/GeoSTAC Coordinator
GIS Training and Research Center
Idaho State University
Spring 2006

2. Lecture 3:Lecture 3:
AdvancedAdvanced GeodatabaseGeodatabase

3. Today’s TopicsToday’s Topics
•Advanced
Geodatabase
features
–Geodatabase element
–GDB Design/ reading
schemas
–Domains
–Relationships
–Topology rules and
editing

4. Feature data set
Feature class
Geometric network
Annotation class
Geodatabase ElementsGeodatabase Elements
Geodatabase
Relationship class
Table

5. GDB DesignGDB Design
•A critical step
•UML modeling for
ArcGIS
–IBM Rational Rose
–MS Visio
•Class diagrams

6. Reading SchemasReading Schemas
Structural
Logical
Most data access technologies provide a way for you to query the
schema of a database, and obtain information about the tables,
stored procedures, data types, users, and other content of a database.

7. DomainsDomains
•Spatial
•Attribute
–Range of values (e.g., 0-100)
–Coded values (e.g., 1 = potatoes 2 =
wheat)

8. The Spatial DomainThe Spatial Domain
•The Geodatabase stores all geometry
coordinates as positive integers
–Faster Display, Processing, and Analysis
–Better Compression (DBMS only)
–Efficient for managing topologic
relationships
•Limited to 2,147,423,647 storage units.
–2.14x10
9
meters, or miles, or inches, or ...

9. Example: Spatial DomainExample: Spatial Domain
•All GIS Features Must Fit Within this
Positive, 32-bit Integer Space.
OFF LIMITS
2,147,423,647
2,147,423,647
0
0
The Database’s
Spatial Domain

10. Storing Feature Storing Feature
CoordinatesCoordinates
Two important considerations when storing
feature coordinates in a Geodatabase:
1.All data is stored as positive, 32-bit
integers (Spatial Domain)
2.All data must maintain a Coordinate
Precision.

11. Coordinate PrecisionCoordinate Precision
•The geodatabase converts all
coordinates into 32-bit Storage Units.
•Storage Units are the smallest
measurable unit that can be stored in a
Geodatabase.
•Precision is used to convert coordinate
system units into storage units.

12. Example: Coordinate Example: Coordinate
PrecisionPrecision
Floating Point
Coordinate in ArcGIS
(123.456000)
Multiply by Precision
123.456789 × 1000
Divide by Precision
123456 ÷ 1000
Integer Storage Unit
in a Geodatabase
(123456)
X = 123.456789
Precision =1000
•Precision is a Scale Factor
–Used to preserve decimal places before
rounding
–Larger precision preserves more digits

13. Example: Precision Example: Precision
PreservationPreservation
Coordinate
system units÷
Precision=
Storage
units
Meters 100 1 cm
Meters 1000 1 mm
Meters 50 2 cm
Feet 12 1 inch
Coordinate System Units
Precision
Storage Units =

14. RelationshipsRelationships
•Connect spatial
data to its attribute
data
•Implement and
enforce referential
integrity

15. Flat Files
Flat files are easier to understand
Difficult to manage and manipulate
Larger file size
Relational Databases
Relational databases more difficult to implement
Reduce data redundancy
Data integrity is improved
Relational vs. Flat-FilesRelational vs. Flat-Files

16. Database includes multiple tables
Tables contain a single subject
Tables are joined by relationships
Examples of relational database
programs:
–Microsoft Access
–Microsoft
®
SQL Server™
–Oracle
–DB2
–FoxPro
What is a Relational Database?What is a Relational Database?

17. Eliminate duplicate information
Assist in querying data
Simpler to manipulate data
Reduce disk space
Why Use a Relational Database?Why Use a Relational Database?

18. RelationshipsRelationships
•Determine where
relationships exist
between tables
•Determine the type
of relationship that
exists
–One-to-one
–One-to-many
–Many-to-one
–Many-to-Many

19. One-to-One One-to-One
RelationshipsRelationships

20. Most common type of relationship
Related between primary and foreign keys
One-to-Many One-to-Many
RelationshipsRelationships

21. Not directly supported between tables
Use a junction table to relate
One order, many products
One product, many orders
Many-to-Many Many-to-Many
RelationshipsRelationships

22. Design Jargon and SymbolsDesign Jargon and Symbols

23. Symbolizing a TableSymbolizing a Table
•Table name
•Divider
•List of all
attributes
stored in this
table as they
will appear in
the table
Parcels
Parcel_ID
TRS
Value
Zoning

24. Symbolizing RelationshipsSymbolizing Relationships
•Draw schematic of RDB
•Determine relationship
fields
•Connect
Table A
Table B
A_ID
Relate_field
B_ID
Relate_field

25. •One-to-one
•One-to-many
•Zero?
Symbolizing Relationship Symbolizing Relationship
TypesTypes
Table A
Table B
A_ID
Relate_field
B_ID
Relate_field

26. TopologyTopology
•Definition: The physical layout of a
network
•“The relationship among features
within a GIS dataset”.
–Shapefiles are NON-Topological
–Coverages are Topological
•Basic topology (area, perimeter, ID’s,
etc.)

27. Full TopologyFull Topology
•“The spatial relationship among
feature classes participating in a
topology layer”
–Must belong to a feature dataset
•Feature classes share geographic reference
system,
•and spatial domain.
–More realistic representation of data

28. Full Topology RulesFull Topology Rules
•User managed
•Customized

29. Polygon RulesPolygon Rules

30. Key ConceptsKey Concepts
•This topic provides you with knowledge
in GIScience.
•You will learn/experience some GIS-
housekeeping.
•You will learn/experience new and
advanced techniques and
applications.

31. Questions?Questions?