Benefits of Parcel Fabric vs. Topology?

[Zeke]

What is the advantage of using a Parcel Fabric vs. using a topology?

The two advantages I know of are that the Parcel Fabric will allow use of the Maps & Apps (phrase drilled into my head at the UC last week), and that a fabric can have associated features in order to maintain spatial relationships. A topology would need to be periodically validated and corrected. But the work involved in migrating all our polygon parcel data into a fabric seems pretty substantial, so maybe a topology, which we (I) would have to create anyway, would be sufficient for our needs.

I'm also unclear whether using a fabric involves editing each individual parcel. This seems like a lot of work compared to a typical workflow of using a cogo traverse around a block and splitting parcels out. Are there other advantages of a fabric I'm missing? Thanks.

[Zeke]

Thanks Ryan. So basically, use a topology to clean up the data, then relatively simple to import it into the fabric? I had that idea, but some of the help online and at the UC made it seem more confusing - using XRay, editing xml files, etc. Maybe that's more intended for data in the Local Government model.

That said, cleaning up errors will take a while. I've got a feeling curves and vertices will be needing lots of work. A lot of previous data was entered into Arc by folks more used to CAD. I'll probably try a subset, see how it goes.

[Zeke]

I'll look for the white paper. Thanks for the offer, may take you up on it ata a later date. Couple other kettles boiling right now, but this is a project I'd like to get on sometime soon.

[AmirBar-Maor]

Over the last few years, Esri has been focused on thedevelopment of a Parcel Editing solution that leverages the Parcel Fabric datastructure. As such, Iâ??d like to sharewith you some of the benefits weâ??ve identified and heard from users whoâ??vedeployed their editing solutions on top of this underlying data structure.
Benefits of Using a Parcel Fabric
The parcel fabric is designed for parcel maintenance andprovides the following benefits:
1. Data Integrity â?? thetopological relationships between the parcel, lines and point are persisted asan inherit part of the data. This behavior doesnâ??t exist with simple featuresand topologies. When you edit/interact with simple features in a topology, auser might perform an edit that breaks a rule and you must validate and fix theerror to persist data integrity. When you edit/interact with a parcel fabric,the user does not have to worry about that since the fabric maintains thoserelationships and ensures data integrity.
2. Historical Parcels â??Parcel history, or lineage, is a native feature of the parcel fabric. Any transaction, such as a split or a merge,retires the parent parcel(s). The historic parcels are not deleted but markedhistoric automatically and can be viewed in any time, even with a time enabledlayer.
3. Legal Start/End Dates â??Each parcel has a legal start and legal end date that allows you to track thelegal creation of that parcel. This isin addition to the system start and system end date.
4. Record Measurements(COGO) - Therecordvalues or measurements on a line are never changed, even if the line geometrychanges in the parcel fabric. Records values are used to calculate misclosures,legal area and other processes. Each parcel has its own set of lines. Thisallows 2 lines to be connected to the same start and end points yet havedifferent records measurement.
5. Stacked parcel typesâ?? the fabric support stacked parcels that can connect to the same points. Forexample, a subdivision, lot, and tax parcel all use the same points on thesubdivision boundary. If those points move, all the parcel types move. But more importantly, the tax parcel and lotcorners donâ??t break the subdivision boundary.
6. Associated FeatureClasses â?? any adjustment or movements you make to your parcels can beapplied to other simple feature classes (e.g. tax districts, utilities, zoning,etc.) that are associated to the fabric.
7. Backlots - Theparcel fabric manages line points that connect a line to another line withoutbreaking the other line (like a T junction). This helps users persist the record measurements of each parcel uniquelyand avoid the classic backlot issues (single lines with vertices thatcompromise the record measurements) youâ??d run in to using simple features and atopology.
8. Plans â?? the parcelfabric has Plans that manage a group of parcels and can specify the accuracylevel, unit of measure, how the curves are defined and other properties. A planis often used to capture a document reference number and the legal description.
9. Standards Based â?? the ArcGIS for Local Governmentsolution extends the parcel fabric data model to include domain specificattributes and best practices. Theattributes and best practices are based on the National Cadastral standard; andare encapsulated in the Local Government Information Model and Tax ParcelEditing Map. Users can easily adopt andstart working with this data model and it is the basis for all the Land Recordsmaps and apps. And as many begin toadopt this approach, organizations will be able to exchange data (county tocounty, county to state etc.) more easily.
10. Accuracy â?? Eachmeasurement has an associated accuracy. Survey control points can be improvedover time and used to run an adjustment (LSA) in order to improve overallaccuracy and identify blunders.
Esriâ??s parcel editing solutioncontains more than just the parcel fabric data structure. In addition, the following is also provided:
11. Parcel Editor Toolbarâ?? the parcel editor contain tools that are specific for parcel maintenance:merge, metes & bounds, area calculation based on records measurements,construct from parent and many more. It is a ready to use and fully supportedpart of ArcGIS Desktop. Many customers are gravitating to this supported anddocumented functionality and moving away from custom tools they have to developthemselves and support in future releases of ArcGIS. Esri continues to grow and evolve this set oftools so let us know what you think. Ifyou feel something is missing submit a topic on the ideas website and weâ??ll consider it for thenext release..
12. Parcel Workflows:Version 10.1 SP1 of ArcGIS Desktop will include a new tool called ParcelWorkflows that streamlines and improves editing efficiency. This functionalitywill only work with a parcel fabric data structure and will be optimized forthe ArcGIS for Local Government Tax Parcel Editing map. Current users will beable to upgrade their parcel fabric and easily create the editing map bydragging the fabric to the map.
13. Additional Land Records Mapsand Apps - All the maps and apps on the ArcGIS for Local Government ResourceCenter are freely available and designed to work together as a complete system.So as you begin to use the Tax Parcel Editing Map and parcel fabric datastructure, youâ??ll be able to take advantage of other maps and apps that addvalue to you organization. It could be apublic access application, a value dashboard for your assessor/treasurer, or asimple map book.
Hope this helps you to make an informed decision,

Amir

[Zeke]

Thanks Amir, that's very helpful, although #4 confuses me. Two lines connected to the same points with different measurements?

I think running a topology to clean up the data before implementing a fabric seems like it will be the most work. I went to several of the LGM sessions at the UC that Scott Oppman ran, got me interested in the idea. Starting with Land, my area, maybe then see if other depts. like Public Works, Fire, etc, would be interested.

[ChrisBuscaglia]

#4 refers to parcels sharing a common boundary with differnent record measurements.  Typically and historically this has been done with annotation representing the opposing dimensions.  This gives you the opportunity to use feature-linked annotation effectively and even labels for dimensions.

See attached pic.

[Zeke]

Thanks, that makes it a bit clearer, but the still confusing part is where the line on one side is marked 500' , but on the other side the two parcels add up to 499.01'. Maybe not a big difference, but it seems inconsistent. I can see how it could happen from two different surveys, but it looks odd.

[ChrisBuscaglia]

Thanks, that makes it a bit clearer, but the still confusing part is where the line on one side is marked 500' , but on the other side the two parcels add up to 499.01'. Maybe not a big difference, but it seems inconsistent. I can see how it could happen from two different surveys, but it looks odd.

Well, that was sort of the point (no pun intended).  Many times surveyors will not agree on the bearing and distance of a particular boundary, or they may be using different basis of bearings, making the recorded bearings/distances different for the same boundary.

You can think of the survey that states N90-00-00E 100.00 ft. (N89-45-00E 100.65 R) or something similar to designate 'as recorded' vs. 'as surveyed'.

[StefhanCampos]

Can I publish a parcel fabric in Arcgis Server? Any samples how do that?

[AmirBar-Maor]

Parcel fabrics can be published on ArcGIS Server.
Parcel fabrics cannot be published as a feature service (for editing).