![]() Since most people don’t own a large format printer, you can take the files to places like Staples and have copies printed for a reasonable charge. Today they can be downloaded for free at. However in thick fog or snow the use of a compass is critical to avoid getting lost.įor years the only way one could get a USGS topo map was to buy them via mail order through the USGS or purchase them from a specialty map store. People who are expert in the use of a topographical map rarely need to use their compass they navigate by associating the terrain with the map. The physical size of USGS topo maps north of 31 degrees latitude are 22” X 27” and south of 31 degrees latitude they are 23” X27” in size. These 7.5 minute Topo Maps are rather large, which provide very detailed information. (As you go south the distance between longitude degrees increases because the earth is a globe). These maps cover 7.5 minutes of longitude and latitude and vary between 49 and 70 square miles in coverage, dependent on the location. Today one can get the declination of any location in the US at this website Mapsįor decades the “gold standard” for backpacking maps has been the 7.5 minute US Geological Survey (USGS) Topographical Maps. Years ago, before the Internet, many people would discard old maps and purchase new ones with current and more accurate declination information. Fact is you cannot accurately navigate without compensating for magnetic declination. ![]() No one challenged me or questioned the method, which was surprising because if one is expert at map and compass it should have been obvious that the procedure I explained was flawed. Picture courtesy of Wikipedia Ī few years ago I was in a trolling mood and on a backpacking forum I stated that knowing declination was not needed and proceeded to lay out a procedure on how to navigate without using declination. This difference between True North and Magnetic North is known as magnetic declination. The North Pole (true north) is the point where all the lines converge in the upper right of the picture. The picture below shows how the magnetic north (blue line) has moved since the 1590, and since 1904 it has been steadily moving in a northwesterly direction. Today, 40 years later, it points 11.63 degrees east of True North. For example, when I moved to Palm Springs in 1977 my compass pointed 14 degrees east of True North. Instead, they point to Magnetic North, which is constantly changing. There are very few locations in the US that a compass will point to True North. Your Compass Probably Doesn’t Point North Since my blog doesn’t have the ability to post comments and only handful of people have my email address, there won’t be the typical debate on my blog this subject might generate.īut first, let’s talk about the North Pole, magnetic declination and then look at some common compasses and how they might be used. In this post the protractor will be presented as a serious tool that backpackers may want to consider, and for those who have used and then abandoned a map protractor, perhaps a re-visit might be worthwhile. One piece of navigation equipment I rarely see in use by backpackers is a map protractor. Most backpackers bring a map and compass whether or not they know how to really use it. Of course, with practice you can use a map and compass to figure out your location if you do get lost. We need to keep in mind that the goal of using a map and compass is to always know where you are, not figure out your location because you are lost. Some of the backup maps and compasses in use are less than optimal and in a no-shit-need-to-have situation might be poor options (think button sized compass and a large scale general map). Many of the electronic persuasion carry and map and compass as a backup, which means duplicate items to do the same task, meaning unnecessary weight. ![]() Then there is the fact electronic solutions (GPS and smart phones) can fail or end up with a dead battery. Nowadays the subject includes GPS units, smart phones, base plate compass vs. I am going to show you how to navigate quicker and more accurately with a map and any compass, by using a map protractor.įew subjects elicit more debates among hikers and backpackers than the subject of map and compass.
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