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NB Atlas, Second Edition (Revised 2002) FAQs How can I use the NB Atlas with GPS? You can use the NB Atlas to find a lake or a place you want to go fishing or hunting. Once you’ve located the lake or location on the map, you can read the coordinates of the Latitude and Longitude grid. Enter these coordinates as a waypoint in your GPS receiver and it will guide you to this location by displaying the direction and remaining distance. Latitude and Longitude are displayed in two format in the NB Atlas: 1. In degrees and minutes If you want to determine this location more accurately you can further scale the minute part of the Latitude. Using a metric ruler:
2. Latitude and Longitude in decimal degrees Note: Why is it so important to scale more accurate geodetic coordinates in Latitude and Longitude? Because
Similarly
As mentioned above, the grid in the NB Atlas changes by:
Just to show that small scaling errors in geodetic coordinates can amount to large differences on the ground. 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 field models produced by the Geological Survey of Canada. The 1997 magnetic declination is found at the bottom right hand corner of each pages in the NB Atlas. General What is the Reference System 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 current and official reference system for coordinates in the province. NAD83 is short for the North American Datum of 1983 and CSRS indicates it was referenced to the national framework (see definition below). This supersedes the former NAD27 used from the early sixties to 1978 and ATS77 in uses until the above change in 1999. The Canadian Spatial Reference System (CSRS) is the foundation for determining your position anywhere in Canada. The CSRS provides a multi-component infrastructure, which is fundamental for ensuring compatibility of all geomatics, navigation and other spatial information from various sources. With a new focus on positioning from space, Geodetic Survey Division (GSD) a division under Natural Resources Canada has created a dynamic infrastructure to serve both present and future needs for positioning. The Canadian Base Network (CBN) is designed to serve as the new ground segment of monumented survey control in the Canadian Spatial Reference System. The program was initiated in 1994, in cooperation with the provinces, to complement the Canadian Active Control System (CACS) network. With a nominal spacing of 200 kilometres in the southern latitudes, it provides easily accessible high accuracy control at the centimetre accuracy with respect to the Canadian Active Control Stations. It also provides the means to evaluate the lower layers of traditional monumented control points established throughout the years by various government departments and/or agencies. What is the map projection used in 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. Some projections minimize distortions in some of these properties at the expense of maximizing errors in others. Some projections are attempts to only moderately distort all of these properties. The New Brunswick Stereographic Double projection was chosen to best represent the shape of the province and has the following features. It is a conformal projection selected to provide slightly higher accuracy than other solutions, reasonable distribution of error, single zone solution and secant Azimuthal.
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