Parcel Data Models for the
Geodatabase
Indiana GIS Conference 2012
Welcome
Joyce West
GIS Account Manager
The Sidwell Company
Presentation Agenda
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Parcel-based GIS editing to maintain common
boundaries with:
◦ Polygon Model
◦ Coincident Boundary Model
◦ Parcel Fabric Model
Some background
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Coverage Format
◦ Legacy Esri format
◦ Contain features organized into feature classes-arc,
node, label point, polygon, and annotation
◦ Support shared geometry and polygon adjacency
◦ Maintain topology
Some background
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Shapefile format
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Supports simple point, line, area features
Non-topological geometry
Attributes have one-to-one relationship with shapes
Common for data sharing
Some background
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Geodatabase format
◦ Data storage and management
◦ Uses standard RDBMS products
 MS Access
 MS SQL Server
 Oracle
◦ Map graphics and attributes stored together
◦ Supports relationships and business rules
◦ Supports multi-user access and editing
Geodatabase Editing
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Appropriate software to support
◦ Advanced Cartography
◦ Coordinate Geometry
◦ Create and edit feature relationships
 i.e. feature linked annotation
◦ Topology rules and fix operations
◦ Multi-user editing
◦ Distributed geodatabases
Polygon Model
The polygon model is a simple, straightforward
GIS data model where map features exist as
separate polygons or data layers.
Polygon Model
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Store map features as separate polygons such
as parcels, subdivisions, corporate limits
Edit lines or edit polygons directly
May use cut and paste operations
Placement of edits is user-controlled
Use map topology tools to maintain alignments
in personal or file geodatabase
Run topology checks to insure data integrity
Features on top of
features on top of
features
Can result in this…
Coincident Boundary Model
The Coincident Boundary Model is based on the
concept of using common geography to represent
multiple features. To accomplish this, a linear
feature class is created in the geodatabase that
stores all boundary features.
Common Coincident Boundaries
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Cadastral/Ownership
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Parcel Line
Lot Line
Subdivision
Road Right-of-Way
City/State/County boundary
Easements
Zoning
Govt Districts
 Tax Districts
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Census data
Coincident Boundary Model
Map features occupy the same place in the
same plane
 Map features that are common to two or more
data layers
 User selects which features will participate in
this model
 Assign multiple feature identities or boundary
types
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Coincident Boundary Model
Establish a hierarchy to symbolize map features
 Edit map features as lines, often just by
changing a tag
 After edits, polygons can easily be updated by
querying and extracting lines attributed with the
appropriate features from the editable layer
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Coincident Boundary Model
Coincident Boundary Model
The Parcel Fabric Model
The Parcel Fabric is a data model and
geodatabase maintenance environment
developed by Esri. The Parcel Fabric is a
modeling solution that stores cadastral
information as a continuous surface of
connected parcels.
What is The Parcel Fabric?
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A specialized grouping of
core Arc feature classes
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Control points
Line points
Points
Lines
Polygons (Parcel, Lot, etc…)
Detailed Relationships are
tracked between them
Fabric Sub Layers
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Control Points
◦ Used to run the Least
Squares Adjustment
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Line Points
◦ Track intersections from
adjacent parcels that don’t
require a “Node” point
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Points
◦ Track “Node” points for a given parcel
◦ Often called “Parcel Points”
Fabric Sub Layers
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Lines
◦ Boundary lines of Fabric
polygons
◦ Can be categorized to track
additional line types
Fabric Relationships
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Lines to Points
◦ Every Fabric line know it’s “from” and “to”
Fabric point
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Lines for every boundary
◦ Every Fabric line knows the parcel polygon it
defines the boundary of
Fabric Sub Layers
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Parcels
◦ Parcel Polygon
◦ Can be categorized to track
multiple polygon types
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Results in overlapping
geometry
Data Integrity and
Redundancy
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Topological accuracy is ensured
◦ Joining parcels with shared points
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Each parcel has its own set of lines
◦ Overlapping for a common boundary
◦ More lines define relatively fewer points
012
31
32
33
34
9
Points
16
Lines
Parcel Fabric Editing
Parcel editor toolbar in core
 Editing workflows allow easy input of fabric
features
 Simple merge and split functions
 Groups transactions by Plans
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Parcel Fabric Benefits
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Improves data accuracy
◦ least squares adjustments
Adjusts related features
 Automatically stores historical geometry
 Topology rules can be established between
features and the fabric
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LGIM
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Local Government
Information Model
◦ Organization of data
◦ Extends use of GIS
◦ Easy to deploy Maps & Apps
Parcel
Fabric
Layer
In Summary
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Polygon Model
◦ Run topology checks
◦ Relies on editor vigilance
◦ May take more steps
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Coincident Boundary Model
◦ One feature – multiple representations
◦ Keeps polygon edges aligned
◦ Efficient editing
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Parcel Fabric Model
◦ Interconnected and related point, line and polygon features
◦ Automatically stores history
◦ Uses edit wizards and spatial adjustment
Thank you
Joyce West
GIS Account Manager
The Sidwell Company | www.sidwellco.com