Specific Steps in Data Modeling (1) Conceptualize the user's view of data –what are the basic features needed to solve the problem? (2) Select the geographic representation –points, lines, areas, rasters, TINs (3) Define objects, features, and relationships –draw a UML diagram, specify relationships, “behaviors” (4) Match to geodatabase elements –Refine relationships, “behaviors” (5) Organize geodatabase structure, add data

( 1 ) User’s View of Data

( 1 ) User’s View of Data cont.

(2) Select geographic rep.

Steps in Data Modeling (1) Conceptualize the user's view of data –what are the basic features needed to solve the problem? (2) Select the geographic representation –points, lines, areas, rasters, TINs (3) Define objects and relationships –draw a UML diagram, specify relationships, “behaviors” (4) Match to geodatabase elements –Refine relationships, “behaviors” (5) Organize geodatabase structure, add data

Unified Modeling Language Entity-relationship diagrams Design methodologies, diagram notations UML –Not a design methodology –Just a diagrammatic notation based on methods –Endorsed by leading software and database companies HTML

Unified Modeling Language UML Diagrammatic notation = “visual language”... For constructing a data model –Explains, documents on object-oriented structure Drawings, relationships constructed in Visio –Like CAD for Civil Engineering Tools to input a drawing to ArcGIS –input data to the data model

Basic UML Grammer Things –“Classes” sometimes grouped in “Packages” Relationships Diagrams

UML Things

UML Notation Zeiler pp a class is shown as a box top part contains the name of the class lower part contains the attributes methods associated with the class lines connect boxes and indicate relationships

UML Notation ( cont. ) Abstract class –specify subclasses underneath –Mammals w/human or dog feature classes –no new instances Feature Class –Specify subtypes underneath –Human, dog, cat

Example: Chicken Object Model

Graphic courtesy of Maidment et al., ArcHydro team

Objects and Features Object (real world) –in ArcGIS an object is non-spatial –it is NOT a point, line, or area –it has no geographic location –it has no shape attribute in its table –Drainage network, ship, vehicle, … customer, lake, house, etc. Feature (spatial context) –an object that has geographic location –a point, line, area, TIN, raster

Relationships Links between classes, shown as lines One to one One to many Many to many

Relationships (cont.) 1:1 - solid line –one record in Class A linked to one record in Class B “is married to” the class of state capitals linked to the class of states 1:n - solid line with * at one end –one record in Class A linked to any number of records in Class B "owns" the class of states linked to the class of area codes

Relationships (cont.) m:n - solid line with * at both ends –any number of records in Class A linked to any number of records in Class B "has visited” "was never married to" the class of mountain lions linked to the class of wilderness areas

Graphic courtesy of Maidment et al., ArcHydro team

Type Inheritance White triangle Class B inherits the properties (attributes, methods) of Class A the class street inherits from the class transportation network Solid diamond the parts and the whole depend on each other

Graphic courtesy of Maidment et al., ArcHydro team

MeasuredData InstantaneousPoint (ex: CTD) Measurement X Y TimeStamp MeasuringDevice MeasuredType Z InstantaneousPoints Measurement Michael Blongewicz

ArcMarine Geodatabase Overall Geodatabase Feature Class Feature Class Feature Dataset Table Relationship Class

Steps in Data Modeling (1) Conceptualize the user's view of data –what are the basic features needed to solve the problem? (2) Select the geographic representation –points, lines, areas, rasters, TINs (3) Define objects and relationships –draw a UML diagram, specify relationships, “behaviors” (4) Match to geodatabase elements –Refine relationships, “behaviors” (5) Organize geodatabase structure, add data

Data Model Levels Increasing Abstraction Reality Conceptual Model Logical Model Physical Model Human- oriented Computer- oriented

Real World Objects and relationships Database Schema (Object state) Physical Model Modeling Process Conceptual Model Lists, flow diagrams, etc Logical Model Diagram in CASE Tool Graphic courtesy of ESRI

Steps in Data Modeling (1) Conceptualize the user's view of data –what are the basic features needed to solve the problem? (2) Select the geographic representation –points, lines, areas, rasters, TINs (3) Define objects and relationships –draw a UML diagram, specify relationships, “behaviors” (4) Match to geodatabase elements –Refine relationships, “behaviors” (5) Organize geodatabase structure, add data –e.g., Marine Data Model tutorial

Arc Marine Data Model Exercise Exercise and data at dusk.geo.orst.edu/djl/arcgis/ArcMarine_Tutorial/ What to turn in: –Screen snapshot of what your ArcMap session looks like at the end of Section 4 (including dynseg referencing) –Answers to 2 simple questions at end of Section 4 (which cruise? which vehicle?) –Can put all of the above in a single MS-Word document, labeled with your NAME please! Due in Dropbox, May 3rd, 6:00 p.m.

Gateway to the Literature Arctur, D. and Zeiler, M., 2004, Designing Geodatabases, ESRI Press Lowe, J.W., Flexible data models strut the runway. Geospatial Solutions, 13(2): Maidment, D.R., Arc Hydro: GIS for Water Resources, ESRI Press, 203 pp. w/CD. Li, X. and M.E. Hodgson, Vector field data model and operations. GISci. Rem. Sens., 41(1): Wright, D., Blongewicz, M., Halpin, P., and Breman, J., A new object-oriented data model for coasts, seas, and lakes, in Green, D.R. (ed.), Coastal and Marine Geospatial Technologies, London: Springer, in press. –dusk.geo.orst.edu/djl/arcgis/coastgis_book_final.pdf Wright, D.J., Halpin, P.N., Blongewicz, M.J., and Breman, J.B., Arc Marine: GIS for a Blue Planet, Redlands, CA: ESRI Press, in prep and review, due out 2006/7. –dusk.geo.orst.edu/djl/arcgis/book

Resulting Analysis - ArcHydro From Arctur and Zeiler, Geodatabase Design, ESRI Press.