General point feature lifecycle rules

The lifecycles of point features are simpler than those of lines or polygons since they cannot change in size or be split into multiple features.

Creation of point features

When a new real-world object comes into being, a new point feature is created to represent it. If, however, the object is a replacement for a previous real-world object in the same position, the original feature is retained. An example would be if an existing post box was replaced by another post box in the same location.

Deletion of point features

When a real-world object is no longer present in the real world, the point feature is removed from Ordnance Survey’s holding. Ordnance Survey keeps a record to indicate that the feature with this TOID used to exist and notifies the user at the next date of COU supply.

Modification of point features due to real-world change

By the nature of the real-world objects represented as point features in OS MasterMap Topography Layer data, it is unlikely that one will be modified without changing its identity. Therefore, any modification to a point feature as a result of real-world change will result in the deletion of the original feature and creation of a new feature, unless there is a clear reason to identify the resultant real-world object with the original. This applies to both geometric change and change of descriptive group or descriptive term.

Modification of point features due to error correction

When a point feature is found to be incorrectly attributed due to an error or is moved due to the correction of a positional accuracy error, the original feature is retained and appropriately modified.

This section has explained in some detail the lifecycles of features so that users can understand how the data is managed by Ordnance Survey.