Specific Steps in Data Modeling

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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

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( 1 ) Users View of Data
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( 1 ) Users View of Data cont.
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(2)Select geographic rep.
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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

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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

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Unified Modeling LanguageUML

• 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

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Basic UML Grammer

• Things
• Classes sometimes grouped in Packages
• Relationships
• Diagrams

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UML Things
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UML NotationZeiler pp. 97-99

• 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

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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

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Example Chicken Object Model
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Graphic courtesy of Maidment et al., ArcHydro
team
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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

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Relationships

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

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Relationships (cont.)

• 11 - 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
• 1n - 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

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Relationships (cont.)

• mn - 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

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Graphic courtesy of Maidment et al., ArcHydro
team
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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

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Graphic courtesy of Maidment et al., ArcHydro
team
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InstantaneousPoint (ex CTD)
Michael Blongewicz
X
TimeStamp
Y
Measurement
MeasuringDevice
Z
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ArcMarine Geodatabase
Overall Geodatabase
Feature Class
Feature Class Feature Dataset
Table
Relationship Class
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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

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Data Model Levels
Reality
Human-oriented
Conceptual Model
Increasing Abstraction
Logical Model
Computer-oriented
Physical Model
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Modeling Process
Conceptual Model Lists, flow diagrams, etc
Real World Objects and relationships
Logical Model Diagram in CASE Tool
Physical Model
Database Schema (Object state)
Graphic courtesy of ESRI
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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

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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, 600 p.m.

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Gateway to the Literature

• Arctur, D. and Zeiler, M., 2004, Designing
  Geodatabases, ESRI Press
• Lowe, J.W., 2003. Flexible data models strut the
  runway. Geospatial Solutions, 13(2) 44-47.
• Maidment, D.R., 2002. Arc Hydro GIS for Water
  Resources, ESRI Press, 203 pp. w/CD.
• Li, X. and M.E. Hodgson, 2004. Vector field data
  model and operations. GISci. Rem. Sens., 41(1)
  1-24.
• 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.p
  df
• 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

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