New Brunswick Survey Control Network - FAQ
   
 
  1. What Reference System is used New Brunswick?
  2. What is NAD83 (CSRS)?
  3. What is CSRS?
  4. What are NAD27 and ATS77?
  5. What is the Map projection used for New Brunswick?
  6. What are the parameters for the NB Double Stereographic projection and Reference System?
  7. On what coordinate system are the SNB Digital Products?
  8. Can UTM coordinates be used in New Brunswick?
  9. What is NBGeocalc?
  10. How can I convert my GPS coordinates?
  11. What is the magnetic declination?
  12. How can you reach us?
1.  What Reference System is used in New Brunswick?
  The Surveys Act defines the coordinate reference system and map projection used in New Brunswick. Since the amendment of the Act in April 1999, NAD83 (CSRS) is now the official reference system for coordinates in the province.
 
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2.  What is NAD83?
  NAD83 is short for the North American Datum of 1983. CSRS indicates it was referenced to the canadian national framework. This supersedes the former NAD27 and ATS77 used until the change in 1999.
 
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3.  What is CSRS?
  In order to take proper advantage of the Global Positioning System, federal and provincial agencies have established three new layers of control survey networks:

a) The continuously operated GPS sites of the Canadian Active Control System (CACS)
b) The federal high accuracy Canadian Base Network (CBN)
c) The High Precision Networks (HPN's)

These three new layers of control networks not only compliment and densify the existing control networks they were specifically designed for GPS use. All of the layers together form the Canadian Spatial Reference System (CSRS) and supported by the various federal and provincial agencies it has become a very practical and useable tool in today's digital information society.

The important thing to note is that the improvements in network accuracy brought about by the current CSRS version of the NAD83 reference frame are another step towards a consistent system capable of supporting the countries positioning needs today and into the future. This consistency through improved network accuracy enables us to take better advantage of all that GPS has to offer.

 
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4.  What are NAD27 and ATS77?
  Historically, New Brunswick has been in a continuous evolution with respect to its choice of datum. Since the late fifties, New Brunswick is up to the third datum selection. The two datum that were used and discarded are:
  • NAD27 (North American Datum of 1927) is based on the Clarke ellipsoid of 1866. This ellipsoid was adopted for the entire continent of North America as a basis for all geodetic computations. The datum is defined in terms of the values of the station Meade's Ranch, State of Kansas.
  • ATS77 (Average Terrestrial System of 1977) is a geocentric ellipsoid of revolution. It was decided at the time that this mathematical figure most conveniently represents the size and shape of the earth for the Maritimes. ATS77 was in place for over 20 years. Similarly to NAD27, new technological tools like GPS (Global Positioning System) and GIS (Geographic Information Systems) came along and GPS data was not compatible with ATS77 thus forcing users to constantly perform transformation of their field data.
 
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5.  What is the Map projection used for New Brunswick?
  Map projections are attempts to portray the surface of the earth or a portion of the earth on a flat surface such as a piece of paper. The following are always a result of this process: distortion in distance, direction, scale, and area. For example if you scale the distance between two clearly identifiable points on the map (maybe buildings) it may not represent the true distance in the field.

The New Brunswick Stereographic Double projection was chosen to best represent the shape of the province and has the following features. It provides a conformal mapping plane in which angles on the ellipsoid or datum remain the same when mapped onto the plane surface.

Double projection means that the ellipsoidal data is first mapped conformally on a conformal sphere.

 
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6.  What are the parameters for the NB Double Stereographic and Reference Systems?
  Over the years, New Brunswick has progressed using different datum or reference frames. The following table captures all the possible parameters.

New Brunswick Reference Systems
Parameters NAD27
(until 1978)
ATS77
(1978-1999)
NAD83 (CSRS)
(since 1999)
Ellipsoid Clarke 1866 ATS77 GRS80
A Equatorial radius
6378206.4 m
6378135.0 m 6378137.0 m
B Polar semi-diameter
6356583.8 m
6356750.305 m 6356752.3141 m
1/f ----------------- 298.257 (exactly) 298.257222101
Projection New Brunswick Stereographic Double projection
Origin Latitude 46º 30' north 46º 30' north 46º 30' north
Origin Longitude 66º 30' west 66º 30' west 66º 30' west
Gaussian mean radius at origin Non geocentric 6379220.286 m 6379222.285 m
Scale factor at origin 0.999912 0.999912 0.999912
False Northing (Y) 1 000 000 ft 800 000 m 7 500 000 m
False Easting (X) 1 000 000 ft 300 000 m 2 500 000 m
 
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7.  On what coordinate system are the SNB Digital Products?
  Most of SNB's digital or paper maps are in reference to NAD83 (CSRS) and the NB Double Stereographic projection is used for plane coordinates:
  • All cadastral data (PLANET)
  • All enhanced topographic database files (ETB)
  • All digital terrain models (DTM)
  • All digital colored orthophotos

Only the NB Atlas book is still in referenced to ATS77. The difference between ATS77 and NAD83 (CSRS) is on the average 4.3 metres, thus well within the scaling precision of coordinates from the Atlas. In this case, one can easily consider the coordinates equivalent to NAD83 (CSRS) for all intensive purposes.

 
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8.  Can UTM coordinates be used in New Brunswick?
  GPS equipment, especially lower priced receivers, does not support the New Brunswick Double Stereographic Projection. Through their options settings, users can choose either spherical coordinates of Latitude / Longitude or Universal Transverse Mercator (UTM) for plane coordinates.

For your personal use, UTM coordinates can be used. On the other hand it is not the case for all legal or public documents which have to be in accordance with the Surveys Act.

 
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9.  What is NBGeocalc?
  NBGeocalc is a piece of software designed by SNB to help with coordinate conversions and transformations in New Brunswick. It is the accepted standard for transforming coordinates from/to ATS77 and NAD83 (CSRS). It is also a very useful tool to convert in all directions, latitudes / longitudes and UTM coordinates and is available through SNB's Service centres or through our Website at www.snb.ca.
 
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10.  How can I convert my GPS coordinates?
  Unless you have the proper software with you GPS receiver, NBGeocalc is a user-friendly tool to perform all your conversions.
 
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11.  What is magnetic declination?
  Many people are surprised to learn that a magnetic compass does not normally point to true north. In fact, over most of the Earth it points at some angle east or west of true (geographic) north. The direction in which the compass needle points is referred to as magnetic north, and the angle between magnetic north and the true north direction is called magnetic declination. You will often hear the terms "variation", "magnetic variation", "compass variation" or "march of the compass" used in place of magnetic declination.

The magnetic declination does not remain constant in time. Complex fluid motion in the outer core of the Earth (the molten metallic region that lies from 2800 to 5000 km below the Earth's surface) causes the magnetic field to change slowly with time. This change is known to as secular variation. Unfortunately, the annual change corrections given on most of these maps cannot be applied reliably if the maps are more than a few years old since the secular variation also changes with time in an unpredictable manner. If accurate declination values are needed, and if recent editions of the charts are not available, up-to-date values for Canada may be obtained from the most recent geomagnetic reference (http://www.geolab.nrcan.gc.ca/geomag/magdec_f.shtml) field models produced by the Geological Survey of Canada.

The 1997 magnetic declination is found at the bottom right hand corner of each page in the NB Atlas Second edition.

 
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12.  How can you reach us?
  We are located in Fredericton, New Brunswick. The Control Survey staff is part of the is part of the Land Registry Unit within Service New Brunswick and we can be reached as follows:

      Director of Surveys
Service New Brunswick
985 College Hill Road
PO Box 1998
Fredericton, NB E3B 5G4
Tel (506) 457-6933
Fax (506) 444-3033

If you require information and you contact us via email, do not forget to include your name and telephone number so that we can reach you.

 
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