A boundary shifts on a new diagram although the fence has not moved

If comparison of an old plan and a new diagram shows a boundary shift, this does not necessarily mean a fence was moved or neighbouring land occupied. Documents may use different coordinate systems, scales and point-position accuracies. Each diagram's origin and suitability for alignment must first be established. Overlaying pictures without checking source data can create a convincing but unreliable impression that boundaries overlap.

What needs to be clarified

The task could distinguish a documentary discrepancy from the actual boundary position and identify the data needed to examine a possible property-register error.

Materials to prepare

Register extracts and point-coordinate documents identifying the coordinate system and data date.
Earlier plans, boundary-survey materials and information on how they were prepared.
Field measurements, accuracy information and photographs of existing fences.

What to compare

Whether coordinates can be compared directly or require a justified transformation.
Whether point identities, boundary traversal order and land description correspond.
How documented positions relate to measured objects and source-data uncertainty.

Possible outcome of the analysis

A possible output is a comparison diagram identifying its data, established discrepancies and further information needed to examine the apparent shift.

Limits of the conclusions

A public map or fence photograph does not replace coordinate data and necessary measurements. Technical analysis alone does not determine ownership or make every mismatch a proven register error.