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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)
A
B
command line interfaceUnix, NT, WindowsArcView as interface
Georelational Data Model:“Classic” ArcInfo and ArcView
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
• 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
gray geodatabase
green shapefile
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
• 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
TemplatesPre-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 ModelsAdministrative BoundariesAgricultureBasemapBiodiversity/ConservationCadastre 2014Defense/IntelEnergy UtilitiesEnvironmental Regulated FacilitiesHistoric PreservationHydrographic/Navigation (IHO)
Local GovernmentMarinePetroleumPipelineSystem ArchitectureTelecommunicationsTransportationWater UtilitiesWater Resources (Hydro, Groundwater)ForestryGeologyLand 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
• 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
Purpose of Arc Marine, Arc Hydro and others
Arc Marine Design Strategy
“Generic”
Marine Data Model
User Group
Data Model
User Group
Data Model
User Group
Data Model
Project
Data Model
Project
Data Model
Project
Data Model
Inh
erit
ance
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 (object-orientation)
• 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 GeodatabaseOverall Geodatabase
Feature Dataset
FeatureClass
Table
RelationshipClass
Real World Objects and relationships
DatabaseSchema
(Object state)
(3) Physical Model
Modeling Process(1) Conceptual ModelLists, flow diagrams, etc
(2) Logical ModelDiagram in CASE
Tool
Graphic courtesy of ESRI
Data Model Levels
IncreasingAbstraction
RealityReality
Conceptual ModelConceptual Model
Logical ModelLogical Model
Physical ModelPhysical Model
Human-oriented
Computer-oriented
(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 NotationZeiler 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 – specify subclasses
underneath– no new instances
• Feature Class– Specify subtypes
underneath
Food
VeggiesMeats
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
• Solid diamond
– the parts and the whole depend on each other
lecture lab
Graphic courtesy of Maidment et al., ArcHydro team
Real World Objects and relationships
DatabaseSchema
(Object state)
(3) Physical Model
Modeling Process(1) Conceptual ModelLists, flow diagrams, etc
(2) Logical ModelDiagram in CASE
Tool
Graphic courtesy of ESRI
or XMI file
(3) Physical
Using a Design TemplateSchema Wizard reads repository or XMI
to create a geodatabase
or XMI file
(3) Physical
Data Model Levels
IncreasingAbstraction
RealityReality
Conceptual ModelConceptual Model
Logical ModelLogical Model
Physical ModelPhysical Model
Human-oriented
Computer-oriented
Real World Objects and relationships
DatabaseSchema
(Object state)
(3) Physical Model
Modeling Process(1) Conceptual ModelLists, flow diagrams, etc
(2) Logical ModelDiagram in CASE
Tool
Graphic courtesy of ESRI
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
Raster in
WGS84
extract_west Shifted_west
Output
grid name
Extract_east
Raster in
WGS84
Extract by
Rectangle (2)Output
Extent
Output
Extent
Output
Extent
Shift
Extract by
Rectangle (3)
Extract by
Rectangle
Mosaic
Output
Extent
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• 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