How to Read a Map & Compass

A good map in your pocket is a reliable tool and is still highly recommended when venturing into the outdoors. It doesn’t run out of power and you don’t have to depend on satellite reception.  Basic compass skills also never go out of date. For an introduction to map and compass use, click here. 

Compass caution in New York-New Jersey:  Be aware that the New York-New Jersey area has many iron mines scattered about that can affect the accuracy of a compass. It is also worth noting that you will be off by about 90 feet per mile for each degree of error, so ignoring the difference between magnetic north and true north can result in a serious error. The declination changes with time. Look at the date of the declination information on any USGS topo and be aware that it could be off by a few degrees if it is not a recent map.

UTM Grids: The New Way of Using Maps

Our maps are equipped with Universal Transverse Mercator (UTM) grids, marked by fine blue lines forming kilometer squares (1,000 meters or about 0.62 miles). For Catskill Trails, each square measures 2 km. These grids help you quickly estimate distances and, when paired with a GPS receiver, accurately pinpoint your location. Make sure your GPS is set to UTM coordinates and use the NAD83 map datum for the best results.

The map edges feature “northings” (distance north of the equator) and “eastings” (distance from the centerline of Zone 18, covering New York). For instance, on our East Hudson Trails map 102, you’ll find the Breakneck Ridge Trail trailhead at the intersection of 4588000N and 585000E.