Parcel Data Models for the Geodatabase

1. Parcel Data Models for the Geodatabase Indiana GIS Conference 2012

2. Welcome Joyce West GIS Account Manager The Sidwell Company

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

4. 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

5. 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

6. 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

7. 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

8. Polygon Model The polygon model is a simple, straightforward GIS data model where map features exist as separate polygons or data layers.

9. 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

10. Features on top of features on top of features Can result in this…

12. 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.

13. 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

14. 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

15. 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

16. Coincident Boundary Model

17. Coincident Boundary Model

19. 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.

20. 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

21. Control 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

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

24. Lines to Points • 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 Relationships

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

26. 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 32 31 9 Points 16 Lines 33 34

27. 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

28. 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

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

30. In Summary • Polygon 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

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