Arc Hydrology Data Model

An Overview of the Modeling Process

Kim Davis and Tim Whiteaker

Center for Research in Water ResourcesUniversity of Texas at Austin

Introduction• UML—What it is, How to read it• CASE tools—What they are, How they

are used• Build the UML Model with CASE tools• Export to a Repository• Generate C++ code (make a .dll)• Create the schema in ArcInfo 8.0• Do Cool, Fun Stuff…

UML• Unified Modeling Language• Graphical interface to computer

languages• A higher evolution of flow-charts• The standard vocabulary for

Object-Oriented Programming

How to read the UML• Classes (Objects)• Inheritance (Is a kind of…)• Subtypes (Is a specific type of…)• Composition (Is made of…)• Aggregation (Is loosely made of…)

How to read the UML• Classes (Objects)

Have Name Have Attributes Have Methods May have

Extensions May have

Interfaces May participate in

relationships

How to read the UML• Inheritance

(Is a kind of…) Alternatively called

Generalization Passes Attributes down

the diagram tree Passes Methods down

the tree Classes involved are

called Parent and Child Children are also called

Sub-classes

HydroStructure is akind of HydroPoint

HydroPoint is a generalization of HydroStructure

More on Inheritance

Of HydroStructure

How to read the UML

• Subtypes(Is a specific type of…) Used for different

“flavors” of the same object

Have the EXACT same attributes

May have different default values for those attributes

How to read the UML• Composition

(Is made of…) Parent controls

lifetime of Child Implemented in

database by use of key fields (Table Linking)

How to read the UML

• Aggregation(Is loosely made of…) Classes exist

independently of each other

Implemented in database by use of key fields (Table Linking)

CASE tools—Intro • CAD=Computer Aided Drafting• CASE=Computer Aided Software

Engineering• Well suited to modern programs

(object oriented vs. menu driven)• Examples: Visio

Enterprise/Professional, Rational ROSE, ObjectDomain

CASE tools—What they do• Began as flow chart converters• Automate programming tasks

which are repetitive and subject to human error

• Provide graphical format that eases transfer and comprehension of software architecture

CASE tools—ExampleDocument Window

Standard Shapes

“Table of Contents”

Build the UML Model with CASE tools• Decide what objects to create

Brainstorm Continuous refining

• Determine what attributes they have Enough to clearly define object Minimum set to practice good modeling

• Devise methods to give custom behaviors

• Delineate relationships required

Generate C++ Code• Creates the objects you have

designed so ArcInfo can use them• Implements the relationships and

behaviors• Results in a .dll (dynamic link

library) which contains the objects• Add custom code if desired

Create Schema in ArcInfo 8.0• Creates empty tables in the geodatabase• Establishes relationships automatically• Looks to the .dll for information on

custom classes• Allows user to choose which classes to

instantiate• Allows last-minute editing of certain

properties

Schema Creation

• Allows user to choose which classes to instantiate

• Allows last-minute editing of certain properties

Do Cool, Fun Stuff

• Learn more through ESRI tutorials

UML - Visio EnterpriseC++ Code

GenerationSchema Creation

• Nifty Network Demo