Load parcel lines with COGO dimensions

This topic applies to ArcGIS for Desktop Standard and ArcGIS for Desktop Advanced only.

This workflow describes the steps for migrating source parcel data with COGO dimensions to a parcel fabric enabled with the Local Government Information Model. Parcel data that has COGO dimensions most commonly exists in the form of a line feature class that stores COGO dimensions in COGO attributes and a corresponding polygon feature class. Lines are individual, two-point lines that have a single set of COGO attributes (lines are not polylines). COGO attributes may or may not be correct.

When preparing data for loading to a parcel fabric enabled with the Local Government Information Model, it is recommended that data be formatted and then loaded into a staging geodatabase. In the staging geodatabase, parcel data is separated by type and topologies are created for each parcel type. Topologies are loaded into the parcel fabric from the staging geodatabase using the Load A Topology To A Parcel Fabric geoprocessing tool.

Repair geometries

Before migrating data to the parcel fabric, it is beneficial to check for and repair bad line geometries. Examples of bad geometries are lines that have null geometries (empty Shape fields), lines that self intersect and lines that have duplicate vertices. Run the Check Geometry geoprocessing tool located under System Toolboxes > Data Management Tools > Features to check for and generate a list of lines with bad geometries. Run the Repair Geometry geoprocessing tool located under System Toolboxes > Data Management Tools > Features to repair bad line geometries.

Check and convert curves

Use the Curves And Lines add-in to convert any curves in the form of densified arcs or polylines to true curves. A densified arc is a series of straight lines that form a single, selectable curved line. The densified arc may have a single set of curved COGO attributes. Densified arcs are most commonly seen in lines that have been converted from coverage format to feature class format.

You can also use this add-in to split polylines into individual, two-point line segments.

Natural boundaries

In some cases, a polyline represents a natural boundary such as a river. In these cases, you do not want to split the polyline up into individual segments prior to migration. These polylines can be migrated as natural boundaries or as line strings to the parcel fabric. You can control whether or not a polyline is migrated as a natural boundary by modifying the Minimum Line String Segment Count tolerance on the Load a Topology to a Parcel Fabric dialog box of the Load A Topology To A Parcel Fabric tool . For example, if you specify a tolerance of 20, polylines with more than 20 segments will be migrated as line strings. Polylines with less than 20 segments will be split into individual parcel lines.

Check COGO attributes

You can track which COGO attributes are generated from line geometry and which COGO attributes reflect the record using the Calculated field on the lines table. Set the Calculated field = 1 if COGO attributes for the line have been generated from the line geometry.

Before migrating data to the parcel fabric it is beneficial to check stored COGO attributes against the actual line geometries. For example the distance attribute of a line is stored as 200 feet but the actual distance of the line shape geometry is 20 feet. These inconsistences should be removed before migration to the parcel fabric to avoid difficulties when editing these parcels in the parcel fabric. Delete the inconsistent COGO attribute. During the data loading process, the empty distance attribute will be populated with the distance of the line geometry.

To check COGO attributes for inconsistencies, follow these steps:

Steps:

1. Download the Parcel Fabric Data Migration and Analysis Tools from the Geoprocessing Model and Script Tool Gallery from the land records resource center and unzip the contents.
2. Use the Flag Source Lines with Bad Distance on Selected Lines and Flag Source Lines with Bad Bearings on Selected Lines tools in the Fix Bad COGO attribution toolbox to detect inconsistent bearing and distance dimensions.
3. Run the Null Flagged COGO Fields where Calculated = 1 tool to delete (null) inconsistent bearing and distance attributes.

   Attributes with NULL bearings and distances are recalculated and populated from the line geometries during the data migration process.

4. If necessary, run the Strip Bad Characters from Direction Field in Quadrant Bearing format tool to remove incorrect letters from dimensions stored in quadrant bearing.

Generate polygons from lines

After repairing line geometries and converting curves, it may be necessary to rebuild the parcel polygons. If you do not maintain parcel polygons, you still need to build polygons from you parcel lines to migrate to the Local Government Information Model. Use the Feature To Polygon geoprocessing tool located under System Toolboxes > Data Management Tools > Features to build polygons from lines. Attributes from the original polygons will need to be transferred to the newly built polygons.

Load data to the staging geodatabase

When loading source parcel data to a parcel fabric enabled with the Local Government Information Model, it is recommended that data be prepared and formatted, prior to migration, in a staging geodatabase. In the staging geodatabase, source parcel data is typed using the model types and attribute domains are applied. Parcels types are loaded into separate feature datasets for each type. Topologies for each feature dataset type are validated and loaded into the parcel fabric.

Depending on the parcel types you maintain, you might need to load parcel data into all or some of the staging feature datasets.

Download and unpack the staging layer package

The Tax Parcel Editing Map on the Land Records resource center contains a schema-only layer package file that you can use as a staging environment in your staging geodatabase. Your staging geodatabase should not be the same geodatabase as your production geodatabase that holds the target parcel fabric enabled with the Local Government Information Model.

To download and unpack the staging layer package, follow these steps:

Steps:

1. Create your empty staging geodatabase.
2. Download the Tax Parcel Editing Map from the land records resource center and unzip the downloaded contents.
3. In the Catalog window in ArcMap, navigate to the \Application\Migration Tools folder, right-click the layer package, and click Unpack.
4. On the Import Schema Package dialog box, navigate to and add the location of your staging geodatabase.
5. Click the Show Details arrow, choose the Other option under Spatial Reference, and specify the spatial reference of your parcel data. Click OK to unpack the layer package.

   Once the layer package has been unpacked, staging feature datasets for each parcel type are created in your staging geodatabase and are added to the map. Make sure to save the map document.

   

Type your parcel polygons

Before loading your source parcel data into the staging feature classes, you need to type your parcel polygons using the Local Government Information Model lrParcelType domain. Parcel types are stored in the Parcel Type (Alias: Parcel Type, Name: Type) field on the parcel fabric Parcels table. If you have additional subtypes for your parcel types, you need to recalculate your subtypes to match the attribute domains used for the different parcel types in the Local Government Information Model. If you do not have additional subtypes on your parcel types, you still need to apply any attribute domains used for the parcel type after loading to the staging feature classes. For example, your lot and unit parcels (if you have them) should be set to or recalculated to type 6 (Lots and Units). Then you need to set the subtype of the lot using the SimConDivType field (alias of Lot or Unit Type), which uses the lrSimConDivType attribute domain.

Type your parcel lines

Your parcel lines need to be typed to be loaded with their related polygons into the staging feature classes. Parcel lines are typed with the same types as their related polygons. Parcel line types are stored in the Parcel Type (Alias: Parcel Type, Name: Type) on the parcel fabric Lines table. To add types to your lines, create a Type field on your lines feature class and follow these steps:

Steps:

1. Use the Select By Attributes command under the Selection menu to select polygons of a specific type.
2. Use the Select By Location command under the Selection menu to select the lines that lie under the selected polygons.

   On the Select By Location dialog box, make sure to check Use selected features under the Source layer dropdown list.

3. Once you have selected your lines, open the lines attribute table and use the Field Calculator on the Type field to populate the selected lines with the appropriate parcel type.
4. Repeat the above steps for all your parcel polygon types.

Load parcel data into the staging feature datasets

Each staging feature dataset contains a parcel polygon feature class, a parcel line feature class, and a topology. The topology contains both feature classes in the feature dataset and also has the required topology rules for data migration using the Load A Topology To A Parcel Fabric geoprocessing tool. In the map, the topology is symbolized to display topology rule errors.

Tip:

If the topology layers are broken in the map, you can fix them by clicking the exclamation point next to the layer and selecting the correct topology in the Set Data Source dialog box.

Attributes and domains that reflect the editing requirements of Local Government parcel maintenance are added to both the parcel polygon and parcel line staging feature classes. These attributes mirror the attributes that are added to the parcel fabric when it is enabled with the Local Government Information Model. The Type5_Subdivisions, Type6_LotsUnits, Type9_Encumbrances, and Type7_HistoricTaxParcels polygon feature classes are symbolized using attribute domains in the map.

The parcel line feature class is symbolized to display lines by line category. The line category used is the same category used by parcel fabric lines.

Polygon types (and their corresponding lines) are queried and loaded into the separate staging feature classes representing each parcel type.

Load parcel polygons

Follow these steps to load parcel polygon types into the staging feature classes in the staging feature datasets:

Steps:

1. In the Catalog window in ArcMap, right-click the polygon staging feature class to which you want to load data and click Load > Load Data.

   

2. Click Next on the Simple Data Loader dialog box to begin using the simple data loader wizard.
3. Navigate to your source parcel polygon feature class and add it to the List of source data to load. Click Next.
4. Make sure that I do not want to load all features into a subtype is chosen and click Next.
5. In the next step of the wizard, map the fields of your parcel polygon feature class to the fields in the staging feature class. Click Next.

   Different fields will be available depending on which parcel types you are loading. For example, if you chose to load polygons to the Type6Parcels feature class (lots or units), the SimConDivType field (alias of Lot or Unit Type) is available. If you maintain subtypes for your lot parcels, you need to have recalculated the subtype values to match the values of the SimConDivType domain on the SimConDivType field (alias of Lot or Unit Type). If you do not maintain subtypes for your parcel types, you still need to calculate attribute domains for parcels on the SimConDivType field (alias of Lot or Unit Type) after loading.

   

6. In the next step of the wizard, choose Load only the features that satisfy a query and click Query Builder to build a query to load parcels of a specified type. Click Next once you have added your query.

   For example, if you are loading parcels into the Type7Parcels feature class, you will build a query to select parcels of type 7.

   

7. Click Finish on the summary page of the wizard to begin loading parcels.

Load parcel lines

Follow the steps listed above to load your related parcel lines into the appropriate Arcs staging feature classes.

ArcGIS Data Reviewer

Once you have staged and formatted your source parcel data, you can use ArcGIS Data Reviewer to validate your data for loading into the parcel fabric Local Government Information model. ArcGIS Data Reviewer includes checks for validating geometries, topologies and can also perform database checks to check that the correct parcel types and domains are present. See the Evaluating Data Readiness for Loading into the Parcel Fabric and the Evaluating Data Readiness for Loading into the Parcel Fabric (Continued...) blogs for more information on using ArcGIS Data Reviewer for data validation and the parcel fabric.

Validate topologies

Once your source parcel data is typed and loaded into the staging feature datasets, topologies in the feature datasets need to be validated against the required set of topology rules. The topology rules have already been added to the topologies in the staging feature datasets.

After validating topologies, any topology errors need to be fixed before the topology can be migrated to the parcel fabric.

Learn more about minimizing topology errors in the parcel fabric data migration process

Migrate topologies to the parcel fabric

Use the Load A Topology To a Parcel Fabric geoprocessing tool located under System Toolboxes > Parcel Fabric Tools > Data Migration in the Catalog window to migrate your clean, validated topologies to a parcel fabric enabled with the Local Government Information Model. Your parcel fabric should exist in a separate, production geodatabase and not the staging geodatabase.

See Data loading considerations for more information on loading attribute fields, plans and dealing with overlapping polygons.