GPS Setup for this Map Area

In order to use your GPS in this map area you must set the units of your GPS to match the units of this map as follows:

	- Position format: select either lat/long or UTM/UPS.
	- Map datum/projection: NAD83
	- Units: metric
	- North reference: true
	- Angle: degrees

For this map, ‘grid’ north is considered to be the same as true north. To learn more about datum and grids go to the website: www.atlas.gc.ca (browse to ‘Learning Resources’ (All Resources) > ‘Map Making’).

To convert between NAD27 Canada and NAD83 projections, go to www.geod.nrcan.gc.ca. To convert between NAD27 Canada and WGS84, go to www.bivouac.com.

If you are using NTS 1:50,000 maps (NAD27 Canada) and want to convert co-ordinates from NAD27 (Canada) to NAD83, you can do this (somewhat laboriously) in the field using your GPS setup as follows:

	Setup:
	- Position format: UTM/UPS
	- Map datum: NAD27 Canada

Read off the co-ordinates of a desired point from the NTS map and create a new waypoint with these co-ordinates.
Go to GPS Setup and change the map datum to NAD83. Go back to the waypoint which will have co-ordinates automatically converted to NAD83 projection.

To convert from NAD83 to NAD27 (Canada), read the co-ordinates off the Southern Chilcotin Trail Map and create a waypoint with map datum set to NAD83. Go to GPS Setup to change datum to NAD27 (Canada). Go back to the waypoint which will have co-ordinates automatically converted to NAD27 projection.

GPS Lessons – Helpful Hints

Your GPS works by receiving signals from 24 available NAVSTAR satellites which move constantly. You can receive these signals anywhere in the world regardless of weather. The more satellites your GPS receives and the stronger their signals, the more accurate your position will be measured. Conversely, the less satellites your GPS receives combined with weak signals, the less accurate your position will be measured. Overhead objects (such as trees) or limited sky (due to mountains or canyons) contribute to less accuracy.

Lower elevations of this map area are typically under thick coniferous forest or within canyons/narrow valleys and so GPS readings can be difficult here. Be patient. Keep your GPS held upright and high. Luck is involved in getting good readings here – favorable satellite positions make for easier readings. Occasionally, however, a reading can not be made. In this case, move on a little and try again – sooner than later your reception will improve. You need reception with 3 satellites to achieve a 2D position fix and 4 or more to also get an elevation measurement.