Models and Structures of ArcGIS
UML and Data Modeling Elements
Model / Data Model
• Model = representation of something in
the real world, of a process in the real
world - how the world WORKS
• Data Model = representation of data or
information ABOUT that something or
process - how the world LOOKS
– limited representation of reality
• a discretization or partitioning of space
• constructs for representation in a computer
Data Model
• usually a representation of the data
collection process
• FIELD … “grid”
• OBJECT … “isoline”
• FIELD or OBJECT … “geo-relational”
• “Delauney triangulation” (alternative)
• partition areas based on “influence” of sample points (Thiessen polys)
e.g., trusted elevation benchmarks or VIPs, market area delimitation, rain gauge area
assignment, etc.
3 Data Models
• geo-relational coverage (object view;
from classic ArcInfo)
• geo-relational shapefile (object view;
from ArcView)
• geodatabase (object-oriented; from
ArcGIS)
Georelational Data Model:
“Classic” ArcInfo and ArcView
command line interface
Unix, NT, Windows
ArcView as interface
A
B
Data Structure
• the way in which the data model is
represented in the GIS
• concerned simply with what can be computed
and what can’t
• not tied to process at all
• DEM/raster for field model
• coverage/shapefile for ESRI geo-relational
(object model)
• contour for isoline variation on object model
• TIN for Delauney triangulation/Voronoi model
• geodatabase for OO geodatabase
Data Structures
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ArcInfo coverages
ArcView shapefiles
ArcInfo grids, USGS DEMs
Images (e.g., georeferenced tiffs)
TINs
Geodatabases
ESRI Coverage as a Data Structure
Image courtesy of Louisville/Jefferson County Information Consortium, Kentucky
ESRI “Shapefile”
.shp — shape format; the feature geometry itself
.shx — shape index format; a positional index of the feature
geometry to allow seeking forwards and backwards quickly
.dbf — attribute format; columnar attributes for each shape,
in dBase III format
.prj — projection format; the coordinate system and
projection information, a plain text file describing the
projection
.sbn and .sbx – spatial index
.xml — metadata in XML format
ArcGIS Icons
( Zeiler, pp. 65-71 )
yellow coverage
green shapefile
gray geodatabase
Geodatabase
If coverages are apples …
and shapefiles are oranges …
The Geodatabase can be your grocery bag…
ESRI Geodatabase Video (3:57 to 11:20)
Elements of the Geodatabase
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Feature Datasets
Feature Classes
Relationship classes
Geometric Networks
Domains
Ranges
Coded Values
Topology
Tables
Metadata
And More!!!
Geodatabase
• Features and
attributes as objects
• Relationships among
features
• Validation or editing
rules, behaviors
• “Container” for
– Vector, raster, tabular
data
– Relationships
– Topology
MS-Office
Object Table
Relationships for a feature
Sharing on Steroids:
ESRI Data Models for Geodatabase Templates
Pre-designed schema (skeleton) of
• Objects
-Feature classes
-Tables
• Relationships
• Domains
• Rules
Why Data Models & Gdb Templates?
• Work with users & partners on practical
design projects
• Build useful ready to load geodatabases
• Continue the process with feedback from
real projects
• Support & encourage standards
ArcGIS Data Models
Administrative Boundaries
Agriculture
Basemap
Biodiversity/Conservation
Cadastre 2014
Defense/Intel
Energy Utilities
Environmental Regulated
Facilities
Historic Preservation
Hydrographic/Navigation
(IHO)
Local Government
Marine
Petroleum
Pipeline
System Architecture
Telecommunications
Transportation
Water Utilities
Water Resources (Hydro,
Groundwater)
Forestry
Geology
Land Parcels
http://support.esri.com/datamodels
Arc Marine
dusk.geo.orst.edu/djl/arcgis
Data Modeling for Spatial Analysis
• What is spatial analysis?
– "a set of methods whose results change when the
locations of the objects being analyzed change"
• Methods for working with spatial data
– to detect patterns, anomalies
– to find answers to questions
– to test or confirm theories
• deductive reasoning
– to generate new theories and generalizations
• Inductive reasoning
What is Spatial Analysis (cont.)
• Methods for adding value to data
– in doing scientific research
– in trying to convince others
• A collaboration between human and
machine
• How do we set up the framework for
spatial analysis?
– Data model to data structure
A Georelational to a Geodatabase Model
• coverage and shapefile data structures
– homogenous collections of points, lines, and
polygons with generic, 1- and 2-dimensional
"behavior"
• can’t distinguish behaviors
– Point for a marker buoy, same as point for OBS
• “smart features” in a geodatabase
– lighthouse must be on land, marine mammal
siting must be in ocean
Purpose of Arc Marine, Arc Hydro
and others
• basic template for implementing GIS
projects
– input, formatting, geoprocessing, creating maps,
performing analyses
• basic framework for writing program
code and maintaining applications
– development of tools for the community
• promote networking and data sharing
through established standards
“Generic”
Marine Data Model
User Group
Data Model
Project
Data Model
User Group
Data Model
Project
Data Model
User Group
Data Model
Project
Data Model
Inheritance
Arc Marine Design Strategy
Geodatabase Concepts
• ESRI's new data object-oriented data model
– objects, features, behaviors
• Geodatabase
– collection of feature classes/data sets, rasters, TINs
– all data in relational tables
– behavior is coupled with features through rules (objectorientation)
• Feature data set
– Contains feature classes
– defines topological role of features
– has a coordinate system
• Feature class
– stored in a relational table
– special field for geometric shape
– geometric data incorporated into the database
• Point, multipoint, segment, path, ring, polyline, polygon
Geodatabase Feature Class
Geometries
ArcMarine Geodatabase
Overall Geodatabase
Feature
Dataset
Feature
Class
Table
Relationship
Class
Modeling Process
(1) Conceptual Model
Lists, flow diagrams, etc
Real World
Objects and
relationships
(2) Logical Model
(3) Physical
Model
Database
Schema
(Object state)
Graphic courtesy of ESRI
Diagram in CASE
Tool
Data Model Levels
Humanoriented
Reality
Conceptual Model
Increasing
Abstraction
Logical Model
Computeroriented
Physical Model
(1) Conceptual - User’s View of Data
(1) Conceptual - User’s View of Data
Conceptual - cont.
(2) Logical - UML
• Unified Modeling Language
• Diagrammatic notation = “visual
language”...
• For constructing a data model
• Drawings, relationships constructed in
Visio
• Tools to input a drawing to ArcGIS
– input data to the data model
From (1) Conceptual
To (2) Logical
UML Notation
Zeiler pp. 97-99
• a class is shown as a
box
• top part: name of class
• lower part: attributes
• methods associated
with the class
• lines connect boxes,
indicate relationships
Graphic courtesy of Maidment et al., ArcHydro team
UML Notation ( cont. )
• Abstract class
Food
– specify subclasses
underneath
– no new instances
• Feature Class
– Specify subtypes
underneath
Veggies
Meats
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
Graphic courtesy of Maidment et al., ArcHydro team
Relationships
(Arc Marine example)
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
Relationships
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
lecture
lab
• Solid diamond
– the parts and the
whole depend on
each other
Graphic courtesy of Maidment et al., ArcHydro team
Modeling Process
(1) Conceptual Model
Lists, flow diagrams, etc
Real World
Objects and
relationships
(2) Logical Model
(3) Physical
Model
Database
Schema
(Object state)
Graphic courtesy of ESRI
Diagram in CASE
Tool
(3) Physical
or XMI file
Using a Design Template
Schema Wizard reads repository or XMI to create a
geodatabase
(3) Physical
or XMI file
Data Model Levels
Humanoriented
Reality
Conceptual Model
Increasing
Abstraction
Logical Model
Computeroriented
Physical Model
Modeling Process
(1) Conceptual Model
Lists, flow diagrams, etc
Real World
Objects and
relationships
(2) Logical Model
(3) Physical
Model
Database
Schema
(Object state)
Graphic courtesy of ESRI
Diagram in CASE
Tool
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 by email or dropbox, April 27th, 6:00
p.m.
Geoprocessing Models
Model Builder diagrams for workflow
Extract by
Rectangle
Extract_east
Output
Extent
Output
Extent
Raster in
WGS84
Extract by
Rectangle (2)
Output
Extent
extract_west
Extract by
Rectangle (3)
Shift
Output
grid name
Shifted_west
Mosaic
Output
Extent
Raster in
WGS84
Use of a Data Model in
an Analysis Model
Model Builder geoprocessing diagrams for workflow
Gateway to the Literature
• Arctur, D. and Zeiler, M., 2004, Designing
Geodatabases, ESRI Press
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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.,
Arc Marine: GIS for a Blue Planet, Redlands: ESRI
Press, 2007.
– In Digital Earth or dusk.geo.orst.edu/djl/arcgis/book.html
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