January 27, 2014


TO ALL BRITISH COLUMBIA LAND SURVEYORS

Re: Official Horizontal Datums for Georeferencing Legal Surveys in British Columbia

The General Survey Instruction Rules (GSIR) were amended December 13, 2013 to require the georeferencing of all but a few legal surveys in British Columbia.

Amendments to Rule 2-6(1) now require that the Surveyor General specify an acceptable framework (datum), expressed in the UTM map projection for georeferencing of legal surveys in British Columbia for all surveys commenced after March 1, 2014.

This circular letter is provided to meet that requirement.

GeoBC publishes the official coordinates of all Active (BC Active Control System (BCACS) and Canadian Active Control System (CACS)) and Passive Control Points within British Columbia on the MASCOT website. On each datasheet listing, the specified datum can be found in a section labelled "Horizontal – Datum" and will be a version of the horizontal datums listed below. An explanation of the version numbering scheme can be found on the MASCOT News site under the heading "NAD83 Coordinate Version Numbering".

Depending on the location of the survey within British Columbia and the method used to complete the required georeferencing the acceptable datums are:

  1. NAD83(CSRS) 4.0.0.BC.1   Mainland BC (not within the GVRD)
  2. NAD83(CSRS) 4.0.0.BC.1.GVRD   Greater Vancouver Regional District (GVRD)
  3. NAD83(CSRS) 3.0.0.BC.1.NVI   Vancouver Island (not within the CRD)
  4. NAD83(CSRS) 3.0.0.BC.1.CRD   Capital Regional District (CRD)

Typically the closest active or passive control point(s) will determine the appropriate datum to be used in your location. If using multiple active control points to post-process GNSS static baselines or comparing results from active control to results from PPP be sure not to mix different datums.

If using Natural Resource Canada's Precise Point Positioning (PPP) service to derive individual georeferenced coordinates be sure to use the appropriate epoch based on your location and not the default 2010.0 epoch:

  1. NAD83(CSRS) 2002.0   Mainland BC
  2. NAD83(CSRS) 1997.0   Vancouver Island

It is critical that the full version number of the datum (e.g. NAD83 (CSRS) 3.0.0.BC.1.CRD or NAD83 (CSRS) 2002.0) which has been used to derive the georeferenced coordinates be clearly labelled on your plan.

It is the responsibility of the land surveyor to ensure that they are using the approved horizontal datum for all georeferencing of legal surveys within British Columbia.

Yours sincerely,

original signed by Mike Thomson

Mike Thomson, BCLS
Surveyor General of British Columbia