A parcel in the parcel fabric is a delineated area of land or water. In three dimensions, a parcel is a delineated volume of space.
Parcels in the parcel fabric are used to manage and represent the following:
- Land rights—for example, ownership, leases, livestock grazing, and mining.
- Land restrictions–—for example, land-use restrictions and easements.
- Land responsibilities—for example, prevention of fire hazards and taxation.
Parcels can represent rights, restrictions, and responsibilities on the surface of the earth, below the surface, and above the surface.
Parcels in the parcel fabric are also used to manage and represent areas delineated by administrative boundaries. Administrative boundaries delineate jurisdictions or other governmental areas, for example, city boundaries, school districts, and international borders.
Parcels are typically recorded or registered but can also be used to manage and represent customary rights. Some organizations also use parcels to manage conflicts and illegal encroachments.
Parcels are added to the parcel fabric as parcel types. You can provide meaningful names for your parcel types and add as many parcel types as needed by your organization.
Defining parcels
Parcel geometries can be defined in multiple ways from a variety of sources. Usually, parcels are defined by legal descriptions on deeds and survey maps. Legal descriptions define the parcel boundary lines or the parcel corner points.
Different countries have different legislation and different types of legal descriptions. Common types of legal descriptions include the following:
- Metes-and-bounds—Starts from a point-of-beginning and continues with the parcel perimeter being defined by a sequence of boundary lines. Boundary lines are defined using measurements (metes) of directions and distances. In this type of description, parcels may also be bounded by other parcels and have natural or physical boundaries.
- Area descriptions—Uses the areas of parcels that have been previously described. For example, a parcel is defined by combining existing parcels or using a portion (such as the north half) of an existing parcel.
- Coordinates—Defines the parcel perimeter using a sequence of points that have coordinates in a specified spatial reference.
Many countries establish their initial parcel inventory using other sources of parcel descriptions that are cost effective. These sources include digitization of paper maps, imagery, and participatory mapping.
In the parcel fabric, all parcel features are associated to the source that created them using the Records feature class, regardless of their type of legal description. Associating parcel features (points, lines, and polygons) to their originating source document supports future decision-making and provides enhanced defensibility for parcel data in the parcel fabric.
Parcel lineage
When parcels are merged or split, they become historic, and new parcels are created. Over time, as transactions occur, more parcels become historic and more child parcels are created. A parent-child relationship is established between parcels that defines parcel lineage.
Transactions that create historic parcels are described in recorded documents. Recorded documents that define land transactions are represented as a records in the parcel fabric. Through records, the parcel fabric maintains parcel lineage, which is valuable when identifying a chain of title for parcels.
Parcel model
Parcels in the parcel fabric are defined by points, lines, and polygons. The parcel polygon is defined by a closed loop of parcel boundary lines, which store the measurements of the boundaries in COGO attributes. The parcel polygon represents the area of the parcel.
Parcel points represent the parcel corners and have x,y,z coordinates in the parcel fabric spatial reference.
Boundary model
Parcel boundary lines match and correspond to the edges of the parcel polygon. Additionally, parcel boundaries are modeled in the following ways:
- The boundary lines of a parcel can be defined by the same record or by different records.
- A single parcel line is used to represent an identical, coincident boundary between two adjacent parcels.
- Overlapping parcel lines are used to represent adjacent parcel edges that partially overlap and do not lie between the same two points. Examples of overlapping, adjacent boundaries are as follows:
- Adjacent parcel boundaries that are not identical (back-lot parcel boundaries)
- Right-of-way boundaries adjacent to parcel boundaries
- Multiple overlapping boundaries for multiple floors of apartment units
- Boundary line geometries can be represented by two-point straight lines, true curves, spiral curves, or multisegment polylines (used for natural boundaries).
Parcels can have natural boundaries when they are adjacent to bodies of water or rivers.