Parcel Data Models for the Geodatabase Indiana GIS Conference 2012

Welcome Joyce West GIS Account Manager The Sidwell Company

Presentation Agenda Parcel-based GIS editing to maintain common boundaries with: Polygon Model Coincident Boundary Model Parcel Fabric Model

Some background 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 Shapefile format Supports simple point, line, area features Non-topological geometry Attributes have one-to-one relationship with shapes Common for data sharing

Some background 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 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 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 Cadastral/Ownership Parcel Line Lot Line Subdivision Road Right-of-Way City/State/County boundary Easements Zoning Govt Districts Tax Districts 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

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

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? A specialized grouping of core Arc feature classes Control points Line points Points Lines Polygons (Parcel, Lot, etc…) Detailed Relationships are tracked between them

Fabric Sub Layers Control Points Line Points Points Used to run the Least Squares Adjustment Line Points Track intersections from adjacent parcels that don’t require a “Node” point Points Track “Node” points for a given parcel Often called “Parcel Points”

Fabric Sub Layers Lines Boundary lines of Fabric polygons Can be categorized to track additional line types

Fabric Relationships Lines to Points Lines for every boundary Every Fabric line know it’s “from” and “to” Fabric point Lines for every boundary Every Fabric line knows the parcel polygon it defines the boundary of

Fabric Sub Layers Parcels Results in overlapping geometry Parcel Polygon Can be categorized to track multiple polygon types Results in overlapping geometry

Data Integrity and Redundancy Topological accuracy is ensured Joining parcels with shared points Each parcel has its own set of lines Overlapping for a common boundary More lines define relatively fewer points 012 31 32 9 Points 16 Lines 33 34

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

Parcel Fabric Benefits Improves data accuracy least squares adjustments Adjusts related features Automatically stores historical geometry Topology rules can be established between features and the fabric

LGIM Local Government Information Model Organization of data Extends use of GIS Easy to deploy Maps & Apps Parcel Fabric Layer

In Summary Polygon Model Coincident Boundary Model Parcel Fabric Model Run topology checks Relies on editor vigilance May take more steps Coincident Boundary Model One feature – multiple representations Keeps polygon edges aligned Efficient editing Parcel Fabric Model Interconnected and related point, line and polygon features Automatically stores history Uses edit wizards and spatial adjustment

Joyce West GIS Account Manager The Sidwell Company | www.sidwellco.com Thank you Joyce West GIS Account Manager The Sidwell Company | www.sidwellco.com