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18-Geom-B5 Survey Law · May 2014

Question 9 of 12: Hierarchy of Evidence and the Rank of NAD83 Coordinates

Nivaar worked solution (AI-drafted; not reviewed by a licensed engineer)

Notes on this paper

National Exams — May 2014 — 04-Geom-B5 Survey Law. Three hours; CLOSED BOOK, NO CALCULATOR. Twelve questions constitute a complete paper (the first twelve as they appear are marked); most answers require sentence-and-paragraph format. All twelve questions are solved in full below. Content is framed in the Canadian common-law and Ontario land-registration context named by the source.

Reference texts: Survey Law in Canada (Canadian Council of Land Surveyors / Carswell, 1989); Brown, Robillard & Wilson, Brown's Boundary Control and Legal Principles (7th ed., Wiley, 2017); Ontario Land Surveyor educational materials and the Association of Ontario Land Surveyors (AOLS) Survey Review; the Land Titles Act, R.S.O. 1990, c. L.5, the Registry Act, R.S.O. 1990, c. R.20, the Surveys Act, R.S.O. 1990, c. S.30, and the Condominium Act, 1998, S.O. 1998, c. 19; Re Ellenborough Park, [1956] Ch. 131 (C.A.).

Question 9: Hierarchy of Evidence and the Rank of NAD83 Coordinates (7)

Question text not reproduced: the examination questions are © Engineers and Geoscientists BC. Open the official past paper (linked at the top of this page) to read the question, then follow the worked solution below.

In retracing the parcel, the surveyor weighs every kind of evidence in the established hierarchy (dignity) of evidence, in descending order of controlling authority:

1. Natural boundaries and senior rights — a controlling water feature or a senior adjoining title, where applicable.

2. Original monuments — the physical corner markers set to create the parcel. Here, the iron bars: if they are the original monuments and are found undisturbed, they control the corners, because they are the very marks by reference to which the parcel was created and conveyed.

3. Lines actually run and marked on the ground — fences, occupation, and evidence of the original lines that corroborate or locate the monuments.

4. Documented measurements — the bearings and distances on the Reference Plan, used to reconstruct positions where monuments are missing.

5. Coordinates and area — the least authoritative class.

Where the NAD83 coordinates rank. The NAD83 coordinates rank lowest — below the iron bars, and generally below the plan's bearings and distances. Coordinates are computed, derived values: they depend on the datum realisation, the control used, the transformation, and the observation method, and they carry their own uncertainty. A found, undisturbed original monument is direct physical evidence of where the corner actually is; a coordinate is only an indirect statement of where the corner was calculated to be. Where the iron bar and the NAD83 coordinate disagree, the iron bar governs. The coordinates are useful evidence — they help relocate a lost bar, tie the parcel to the spatial reference system, and check for gross error — but they yield to the monument. In short, coordinates are the servant of the monuments, not their master.