About the parcel fabric feature adjustment
This topic applies to ArcEditor and ArcInfo only.
It is common for feature classes to be related to parcel boundaries. For example, road centerline and sewer feature classes must maintain a spatial distance from the boundary of a land parcel, zoning districts must follow the boundaries of land parcels, and building footprints must lie inside the boundaries of land parcels. It is thus typical for feature classes to be edited using parcel boundaries as a background reference. For example, road centerlines are constructed at a specified distance from the road frontage boundary of a parcel.
The parcel fabric acts as a background reference for related feature classes. When the parcel fabric is adjusted through a least-squares adjustment, parcel corner point coordinates may change and update with new values, resulting in discrepancies between the fabric parcels and overlying feature classes. It is important for feature classes based on the parcel fabric to be adjusted similarly, thereby maintaining their relative position.
Parcel fabric feature adjustment is used to realign standard feature classes to adjusted fabric parcel boundaries. If fabric parcels are adjusted in a least-squares adjustment, the parcel corner coordinates may change over time. Depending on the size of the coordinate changes, discrepancies may result between parcel boundaries and the overlying feature class layers. Any feature class that is associated with the parcel fabric can be adjusted by the parcel fabric feature adjustment.
When a set of parcels is adjusted in a fabric least-squares adjustment, vectors are generated between the old and new coordinates of the parcels. The parcel fabric feature adjustment uses these vectors to adjust and realign features in associated feature classes.
The adjustment level
Each time a least-squares adjustment is run on a set of parcels, the vectors generated from the least-squares adjustment are stamped with a date and time. This time stamp corresponds to an adjustment level. When a feature class is first associated with the parcel fabric, its adjusted date, or adjustment level, is set to Not Yet Adjusted. Once features in a feature class are adjusted in a feature adjustment, the adjustment level of the feature class is set to the date and time of the latest least-squares adjustment run on the underlying parcels.
For example, if a set of parcels is adjusted in a least-squares adjustment and there are overlying features that are adjusted in a feature adjustment for realignment, the adjustment level of the feature class is set to the adjustment level that corresponds to the date and time of the least-squares adjustment. If another least-squares adjustment is run on a different set of parcels and different features in the same feature class are adjusted in a feature adjustment, the adjustment level of the feature class is updated to the date and time of the more recent least-squares adjustment run on the underlying parcels.
Only those features that overlay adjusted parcels are adjusted by the feature adjustment.
When first associating a feature class to the parcel fabric, you can set its adjustment level to either your own specified date or an existing adjustment level in the system. In this case, you are telling the feature class that it is already adjusted and current with the date or adjustment level that you specify. The feature class will receive all adjustments happening in the system after your specified date or adjustment level.
Associated feature classes and datasets can have different adjustment levels. You can only set the adjustment level once; after that, the adjustment level is managed by the system.
When features are adjusted in a feature adjustment, an adjustment buffer of 50 meters, or 164.04 feet, is applied to surrounding features outside the adjustment area. A buffer is applied to surrounding features for seamless integration of adjusted features. Smaller and smaller adjustments are applied to surrounding features such that the adjustment vector becomes zero at 50 meters.
You can change the default 50-meter adjustment buffer in ArcObjects using the BufferDistanceForAdjustment property on the IDECadastralFabric2 interface.