Working with the parcel fabric traverse tool
This topic applies to ArcEditor and ArcInfo only.
The parcel traverse is the primary method for entering parcel data in the parcel fabric. For a single parcel on a survey plan or record of survey, dimensions for each parcel boundary are entered in sequence such that a closed polygon is formed.
The parcel traverse environment in the parcel editor facilitates the data entry of parcels using information from plans and records of survey. Recorded dimensions are entered directly from the plan as well as other parcel information, such as the PIN, stated area, and parcel accuracy.
Parcels can be entered either outside the parcel fabric in their own local coordinate system or in the projected map. The Parcel Editor Options dialog box lets you select whether or not to enter parcels in a local coordinate system. To open the Parcel Editor Options dialog box, click the Parcel Editor menu on the Parcel Editor toolbar and click Options.
When entering a parcel traverse in a local coordinate system, no set of coordinates or knowledge of a spatial reference is needed. All that is required are the parcel dimensions, which are on the plat or record of survey.
Once the parcel traverse is complete, the new parcel can either be saved as unjoined or immediately joined to the parcel fabric. An unjoined parcel resides in local coordinate space outside the parcel fabric layer. When joining a new parcel, parcel corner points are matched with the corresponding points in the parcel fabric.
When entering a parcel traverse in the projected map, you can start entering the parcel anywhere within the map extent or you can snap to existing fabric points. You would snap to existing fabric points for reference purposes when entering a parcel traverse.
If snapping to existing points in the fabric layer when traversing a parcel, the parcel still needs to be joined to the fabric, where new parcel points are matched with corresponding points in the fabric.
An incomplete parcel traverse can be saved as unjoined at any time by clicking the Keep changes to parcel data command on the Parcel Details window. After completing a parcel traverse, you can choose to save the traverse and immediately join the parcel the fabric by clicking the Keep changes to parcel data and Join command on the Parcel Details window .
Parcel traverse units
The parcel traverse environment supports most of the common units used for representing recorded information on a plat or record of survey. Units are set on the Plan Properties dialog box, and each plan can have a different set of units.
The following direction, angle, distance, and area units are supported:
Direction or angle type
- Quadrant Bearing
- North Azimuth
- South Azimuth
- Internal Angle
When entering bearings using the Quadrant Bearing format, you can use numbers to specify the quadrant instead of having to type the required letters. This allows you to work solely with the numeric keypad and speeds up the data entry process. The following numbers represent the quadrants in the Quadrant Bearing format:
- 1 = NE
- 2 = SE
- 3 = SW
- 4 = NW
For example, N 45-59-59 E can be entered as 45-59-59-1.
Direction and angle units
- Degrees Minutes Seconds
- Decimal Degrees
Distance and length units
- U.S. Survey Feet
- International Feet
- U.S. Survey Chains
- U.S. Survey Links
- Square Meters
- Square Rods
- Square U.S. Feet
- Square Feet
- Quarter Sections
- Square Meters, Hectares, or Kilometers
- Acres, Roods, or Perches
Circular curve parameters
- Radius and Chord Length
- Radius and Arc Length
- Radius and Central Angle
Circular curve direction
Overriding curve parameters
Sometimes, curves on a plat or plan do not conform to a single set of curve parameters. There may be cases where you will need to enter a curve using different curve parameters from the parameters you specified for the plan. Instead of having to change the curve parameters, you can override the current, set curve parameters in the traverse line entry grid. The following letters can be used to override the current plan curve parameters:
- Chord length—c (or C)
- Arc length—a (or A)
- Delta (central angle)—d (or D)
- Tangent bearing—tb
- Chord bearing—cb
- Radial bearing—rb
For example, to enter a chord bearing when a tangent bearing has been set for the curve, you will enter 54-24-32-1cb or 54-24-32-1-cb (Quadrant Bearing format).
Line categories and feature templates
When entering lines in the parcel traverse grid, you can specify both a line category and a feature template.
Line categories are system defined and are used to represent parcel structure. For example, if a series of boundary lines form a closed loop, a parcel is created. A closed loop of connection lines does not create a parcel. Remaining line categories, such as connection lines and dependent lines, connect to the parcel.
The following line categories are available in the parcel traverse grid:
- Boundary lines are the primary lines and define the parcel boundary. Boundary lines can define closed and unclosed parcels. Boundary line accuracy (Accuracy attribute value) is the same as the parcel polygon accuracy (Accuracy attribute value), unless otherwise specified. If no parcel accuracy is specified, a default accuracy level of 3 is used.
- Dependent lines are part of the parcel and are dependent on parcel boundary lines. Dependent lines should be a looped sequence of lines that start and end on the same point in the parcel. They can be used to define an easement that belongs to the same parcel. Dependent lines can optionally participate in a fabric adjustment, in which case they are treated in the same way as boundary lines.
- Precise connection lines connect a parcel corner point to a control point. Precise connection lines should start at the parcel point and end at the control point and should never start at the control point, that is, be oriented in the reverse direction. The control point is treated as being on the parcel point that the precise connection line starts from. Precise connection lines are used to connect to control points only. Precise connection lines automatically have an accuracy level that is one level higher than the parcel accuracy. For example, if the parcel accuracy level is 3, precise connection lines will have an accuracy level of 2.Caution:
Precise connection lines should not exceed 50 meters (or 164 feet). In a fabric least-squares adjustment, long precise connection lines can effectively constrain the entire adjustment area along the line, making the least-squares adjustment solution unstable. If a precise connection line exceeds 50 meters, it is best to use a standard connection line.
- Connection lines connect parcel points or connect a parcel point to a control point. Connection lines should not start at a control point. Connection lines can also connect between points in the same parcel. Connection lines are often used to connect isolated islands of parcels such that a network is formed. A connected parcel network is required by the fabric least-squares adjustment. Connection line accuracy is the same as the parcel accuracy unless otherwise specified.
- Radial lines are automatically generated and are lines that radiate out from the endpoint of a curve boundary to its center point. Radial lines are always generated in pairs, one for each end of the curve. Radial line accuracy is the same as the parcel accuracy, unless otherwise specified. For very long radial lines, an accuracy level of 7 (excluded) may be necessary in the fabric least-squares adjustment. This is because adjustments to flat curved boundaries can result in larger shifts in the curve's center points, causing the radial lines to become outliers.
- Road frontage lines are set on a parcel's road frontage boundary lines. You would change a parcel boundary line to a road frontage line to use the Maintain straight lines option when running the fabric least-squares adjustment. When using the Maintain straight lines option in a fabric least-squares adjustment, any road frontage lines in adjoining parcels within the same plan that have the same bearing are formed into collinear, straight lines. This is a postprocessing option that is run after the fabric adjustment has completed. Road frontage line accuracy is the same as the parcel accuracy unless otherwise specified. Note:
Road frontage lines should not be used in unclosed parcels.
- Origin connection lines are similar to connection lines but have their line orientation reversed. When entering parcels using the parcel traverse, origin connection lines are entered first, then the parcel boundary lines are entered. Origin connection lines are typically used when there is a connection line required from a point of beginning to a parcel point. Origin connection line accuracy is the same as parcel accuracy unless otherwise specified.
- Part connection lines are used to connect the parts and/or rings of a multipart or donut parcel. Part connection line accuracy is the same as parcel accuracy unless otherwise specified.
In ArcGIS, feature templates are used to create new features. Feature templates help automate the creation of new features in that attributes are automatically populated when templates are specified. In the fabric, you can use feature templates on parcel lines and polygons. For example, you can define a Subdivision line template that automatically sets the line category to Boundary and Accuracy to 3.
The curve calculator
When entering a curve for a traverse line, there may not be enough curve parameters stated on the plan or survey document to complete the curve. You can use the Curve Calculator dialog box to determine the complete set of parameters of a curve from two known parameters.
The Curve Calculator command is found on the COGO toolbar.