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Configuring your GPS for Position Co-ordinates and Map Datums
Written: 2000.07.04 by: Robin Tivy

This article discusses different GPS "Position Formats" and how the Map Datums affect them. Basically older Canadian maps are NAD 27, newer ones are NAD 83, and the GPS internals are WGS 84. Your datum setting has to match the paper map, otherwise your grid references are off by about 200 m.

Review 2016: This article is all about using GPS units with paper maps. In other words, how to figure out where on a paper map a given set of coordinates is located. But now days most GPS have built in maps, and so you never deal with the coordinates or datums at all - the GPS positions the cursor automatically at the correct location on its maps. Only if you were working at home trying to locate a grid reference in an article on GMap would you be concerned about Datums. ORIGINAL ARTICLE As you may know, your GPS has two main types of "Position Format": Latitude-Longitude or UTM Grid

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