In some countries you may need to deduct the variation so check your map! Also in some areas the type of underlying rock formation may affect your compass and whilst this phenomonen is quite rare a little reading up on the area you intend to walk in should reveal any such problems. If your compass bearing off the map is reading say 154 degrees turn the compass housing to add 4 degrees to obtain a magnetic bearing of 158 degrees. For example the "variation" in the UK Lake District is about 4 degrees. Having determined the "variation" adjust your compass bearing. If your map is not a recent one you should update the "variation" using the information printed on the map. To do that look at the information section on your map which will tell you the "magnetic variation" for that area. Therefore before walking off in the direction of the compass bearing you need to adjust from "Grid North" to "Magnetic North". However when you take your compass off the map it will read by reference to "Magnetic North" and so your bearing will be slightly inaccurate. This is not quite the same as "True North" but the difference can be ignored. When taking a compass bearing on the map you will have aligned the compass using the grid lines and your resulting compass reading will therefore be by reference to "Grid North". If you've got any more favorites I'd love to expand this list.įinding North - Adjusting for Magnetic North Did you know that there are three different variations of North? So, let's look at finding "North". As you can see, I've only included maps found for Washington State (except usgs). Unfortunately, the maps are difficult to read when compressed to 8.5x11. Alternatives- For the cash-strapped, you can download USGS maps in pdf form, for free, on their. Includes features like roads, boundaries and streams. Has a map scale or datum that you are comfortable with. Essentially, be sure your map-Covers the entire hike. Compact size Uses lat/long, UTM, UMS coordinates Scale is 1:69500 Cons: Only Available for WA and OR right now, with plans for AZ CA NY and NV. Updated more recently- 1990-84 Both lat/long and UTM Cons: Less detailed Only for Washington 100 foot contour lines Green Trails Maps- Pros: 15 minute coverage Originally based on USGS, but updated frequently. Custom Correct Maps- Exclusive To Washington Pros: 15 minute coverage Scale is 1:62500 Derived from USGS maps, but arranged to show popular loop hikes and trails. Many maps haven't been updated since 1950. Cons: The 7.5minute maps are huge and can be unwieldy. They have WGS84 (lat/long) and UTM coordinate systems. A scale of 1:24000 (1 inch equals 24,000 inches) and line intervals of 50 feet make them pretty detailed. USGS- Pros: USGS maps are the standard for wilderness navigation. Right now I'll stick to what kind of map you'll need, and save map features for later. I think soldiers are human and if they are not pushed to maintain perishable skills those skills are lost.The map is your most important tool, as you can always squeak by without a compass (not recommended!). The physical wear and tear from continous patrols and manning outposts resulted in shortcuts that are now SOP. He also said the Mission load was such that training was almost nonexistant while in country. His accessment was in threater units relied a great deal on electronics and would be at a loss if they suddenly disappeared. He had a few funny stories on his having to relearn the basics in land nav. He had to admit due to the operational tempo basic skills had fallen by the wayside. He had multiple tours in both Iraq and Afganistan and his last unit was Airborne. Got the chance to shoot with an E-6 type who was a Basic Infantry skills Instructor. Re: Analog Navigation in Today's Military
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |