Object-Orientation

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

Gateway to the Literature An, L., M. Linderman, J. Qi, A. Shortridge and J. Liu, 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):

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?

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

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

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

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

Inheritance in Arc Marine

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

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

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

Example Merge Rule

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

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

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)

Arc Marine Data Model FeatureClass: TimeSeriesPoint ObjectClass: Measurement

TimeSeriesPoint with Measurements 1 *

Relationships

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

DHI TimeSeries Manager Data Access Bridges Functionality TimeSeries Controls

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

Data Model Review A practical working templateA practical working template A starting point for creating a geodatabaseA starting point for creating a geodatabase An aid to simplify the integration of similar datasetsAn aid to simplify the integration of similar datasets A way to facilitate the exchange of dataA way to facilitate the exchange of data A support to existing standardsA support to existing standards Feature ObjectIDGeometry LandObject LandObjectIDTransactionIDSystemStartDateOfficialStartDateOfficialEndDate SurveyPoint SurveyBoundary Point Measurement Computation Coordinate Project Geodatabase * * **

Use of a Data Model in an Analysis Model Model Builder geoprocessing diagrams for workflow

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

3D points displayed in volume space

ArcGIS Data Models Web site Over 25 industry-specific data models Conceptual and logical diagrams Case studies, Tips and Tricks documents

Thematic Content - layer stack Thematic groupings of oceanographic data sets

Arc Marine Thematic Layers