Map Datum

Getting to the right destination is important to the backcountry traveler. Setting your GPS to the right Map Datum makes a big difference. Not selecting the right datum could put you hundreds of yards away from your intended location!!!!

Datum is a term that GPS users should be aware of. It is a set-up function and option found on all receivers.

In essence, map datum is a mathematical model used to take information from a spherical earth and adjust that information for placement on a flat map. Of course we can get much more technical but in reality, that is about all the hiker/hunter needs to know.

It is the application of datum that is important to hikers.

Today, most US Geologic Survey (USGS) topographic (topo) maps are based on a map datum called the North American Datum of 1927; or NAD 27. This information is found at the bottom left of a topo.

To read the rest of the article go here.