What is a parcel fabric?
This topic applies to ArcEditor and ArcInfo only.
A parcel fabric is a dataset for the storage, maintenance and editing of parcels. A parcel fabric is created under a feature dataset and inherits its spatial reference from the feature dataset.
A parcel fabric stores a continuous surface of connected parcels or parcel network. Parcels in a fabric are defined by polygon features, line features, and point features. Polygons are defined by a series of boundary lines that store dimensions as attributes in the lines table. Dimensions on parcel lines should ideally match recorded dimensions on the record or survey or plan.
Parcel polygons are linked to each other by connection lines, for example, connection lines across roads. Because each and every parcel is either linked or connected, a seamless network of connected parcel boundaries, or parcel fabric, is formed. Parcel lines have endpoints, which are the parcel corners. Parcel corner points are common between adjacent parcel boundaries, establishing connectivity and maintaining internal topological integrity in the network.
A parcel fabric is made up of these key features:
- Parcel lines, which store and preserve recorded boundary dimensions
- Parcel points, which store x,y,z coordinates derived from a least-squares adjustment
- Parcel polygons, defined by parcel lines
- Line points, which are parcel corner points that lie on the boundaries of adjacent parcels
- Control points, which have accurate, published coordinates for a physical location
- Plans (table), which store information about the record of survey
- Parcel fabric jobs (table), which track edits to the parcel fabric
- Accuracies (table), which weights parcels in the least-squares adjustment
- Adjustment vectors (table), which store sets of displacement vectors from least-squares adjustments
Spatial accuracy in the parcel fabric is improved and maintained through a fabric least-squares adjustment. Control points are processed together with recorded dimensions to derive new, more accurate coordinates for parcel corners. Line dimensions are not changed, but fabric point coordinates are updated. The result is an accurate coordinate-based cadastral system.
The parcel fabric acts as a basemap for overlying feature classes. Feature classes such as building polygons and utility lines are constructed in relation to parcel boundaries. Feature classes using parcel boundaries as a basemap will fall out of alignment with an adjusted parcel fabric. To bring standard features back into alignment with the parcel fabric, coordinate shifts resulting from the least-squares adjustment are captured and stored as displacement vectors in the geodatabase. Displacement vectors are then applied to overlying features in a rubber sheeting process to bring them into alignment with the parcel fabric. The result is features that are aligned with an accurately coordinated parcel fabric.
A parcel fabric is a representation of the record of survey for an area of land. Parcel boundary line dimensions in the parcel fabric match the dimensions on the survey record. Dimensions in the parcel fabric are edited in response to a change in the survey record, for example, a parcel split or resurvey. Parcels that are edited or replaced by new survey records are retained as historic, thus always preserving the original survey record.