Object-Oriented Data Modeling for Collaborative GIS Processes

2. Object-Orientation

3. Gateway to the Literature • Balram, S. and S. Dragicevic, 2006. Modeling collaborative GIS processes using soft systems theory, UML, and object oriented design.Transactions in GIS, 10(2): 199-218. • Whiteaker, T.L., D.R. Maidment, J.L. Goodall and M. Takamatsu, 2006. Integrating Arc Hydro features with a schematic network. Transactions in GIS, 10(2): 219-238.

4. Gateway to the Literature An, L., M. Linderman, J. Qi, A. Shortridge and J. Liu, 2005. Exploring complexity in a human-environment system: An agent-based spatial model for multidisciplinary and multiscale integration. Annals of the Association of American Geographers, 95(1): 54-79.

5. Object-Oriented Data Modeling • Objects in the real world • have “natural” rules and relationships in the computer world • Rivers flow downstream • Roads handle levels of traffic • Land parcels respect landuse laws • How to build this intelligence into data structures?

6. OO Principles • things in the world are instances of classes • John Smith - human being • Harrison Blvd. - street • Corvallis - city • Mary’s Peak - mountain (Hugh Grant’s hill??) • Identity, Inheritance, Encapsulation

7. OO Principles ( cont. )Identity • classes form hierarchies • John Smith is an instance of the class male human beings • male human beings are a subclass of human beings • human beings are a subclass of mammals • mammals are a subclass of fauna • each subclass shares the properties of the class

8. OO Principles ( cont. )Identity • geographic objects often group into complex objects • an airport is composed of runways, hangars, terminals • a state is composed of counties • an area coverage is composed of polygons, arcs, nodes

11. OO Principles ( cont. ):Inheritance • Object can inherit properites • old hierarchical database concept • objects can inherit properties that are true of all objects of that type • e.g., for all polygons • new county in Oregon, still can’t pump gas there • and can also add new properties • e.g., properties true only of a certain class • rural county, always has diesel gas

12. Inheritance in Arc Marine

13. OO Principles ( cont. ):Encapsulation ( Behavior ) • Object can encapsulate behavior (functions) • what kinds of behavior? • editing rules • e.g, corners of a building must be square • might apply to all buildings but not all polygons • might apply only to some buildings • two adjacent objects must have the same common boundary

14. Object-Orientation Graphic From An et al., 2005, Annals of the AAG

15. Behavior ( cont. ) • attribute rules • e.g., range of possible numbers • dates in numerical format (only 1 to 12) • split and merge rules • 1 feature split or 2 features merged, what happens to attributes? • e.g., split a street, the lengths of two parts are shares of the total • e.g., merge two polygons, their population counts are summed for the combined polygon • e.g., merge two polygons, their population densities are averaged, weighted by area

16. Example Merge Rule

17. Behavior ( cont. ) • editing, attribute, split and merge rules • special procedures • e.g., procedure to measure areas of polygons • associated with polygon object type • e.g., procedure to annotate contours • specific interaction rules between objects • e.g., a liquor store cannot be within 500 m of a school • an offramp is required if a street and a freeway intersect • at least one stream must flow out of every stream junction

18. Object-Orientation Graphic From An et al., 2005, Annals of the AAG

19. A “Smarter” Data Model/Data Structure • ArcInfo 7 coverage • geometric information stored in database • ArcGIS geodatabase • stores geometric information as "shape" attribute (better) • Links to object tables of “rules/behaviors” • Identity, Inheritance, Encapsulation (Behavior)

20. Arc Marine Data Model FeatureClass: TimeSeriesPoint ObjectClass: Measurement

21. TimeSeriesPoint with Measurements 1 *

22. Relationships

23. GDB GeoDatabase Bridge ... ... DHI TimeSeries Manager Data Access Bridges dfs ASCII DB XML

24. Data Access Bridges Functionality DHI TimeSeries Manager TimeSeries Controls

25. MIKE 21 ArcGIS MIKE 11 MIKE GIS MIKE Basin DHI TimeSeries Manager Arc Atmosphere Arc Hydro Arc Marine Geodatabase TimeSeries Manager Data Access Bridges dfs0

26. Geodatabase Point Feature ObjectID Geometry Measurement Computation LandObject SurveyBoundary Coordinate * SurveyPoint LandObjectID TransactionID SystemStartDate OfficialStartDate OfficialEndDate * * Project * Data Model Review • A practical working template • A starting point for creating a geodatabase • An aid to simplify the integration of similar datasets • A way to facilitate the exchange of data • A support to existing standards

27. Use ofaDataModel in an Analysis ModelModel Builder geoprocessing diagrams for workflow

28. 3D Interpolation toolSample resulting from collaboration between data models and ESRI developer Network (EDN) New tools based on data model prototypes and case study testing.

29. 3D points displayed in volume space

33. Over 25 industry-specific data models Conceptual and logical diagrams Case studies, Tips and Tricks documents ArcGIS Data Models Web sitehttp://support.esri.com/datamodels

34. Thematic Content - layer stackThematic groupings of oceanographic data sets

35. Arc Marine Thematic Layers

36. Arc Marine Thematic Layers