Models and Structures of ArcGIS

UML and Data Modeling

ElementsLongley et al., 8 (2/e) Zeiler, chs. 4, 5, and 12

Review Zeiler ch. 1

Models for GIS

• representation of reality --> model

• GIS itself is based on a model of complexity

• GIS is used to model complexity• full representation of reality?• data model = limited representation of reality– a discretization or partitioning of space– finite, discrete nature of computing devices

Data Model

• representation of information about the process

• FIELD … “grid”• OBJECT … “isoline”• FIELD or OBJECT … “geo-relational”

• “Delauney triangulation” (alternative)

3 Data Models

• geo-relational coverage (object view; from classic ArcInfo)

• geo-relational shapefile (object view; from ArcView)

• geodatabase (object-oriented; new in ArcGIS)

A

B

command line interfaceUnix, NT, WindowsArcView as interface

Georelational Data Model:“Classic” ArcInfo and ArcView

ArcInfo Coverage as a Data Structure

Image courtesy of Louisville/Jefferson County Information Consortium, Kentucky

Data Structure• not tied to process at all• concerned simply with what can be computed and what can’t

• the way in which the data model is represented in the GIS– DEM for field model– contour for isoline model (variation on object)

– TIN for Delauney triangulation model– coverages, shapefiles for geo-relational– geodatabase for OO geodatabase

Data Structures

• ArcInfo coverages• ArcView shapefiles• ArcInfo grids, USGS DEMs • Images (e.g., georeferenced tiffs)

• TINs• Geodatabases

ArcGIS 9 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…

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

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 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