One of the most important skills necessary for navigating the back country is understanding the proper way of Reading A Map. It is not a difficult skill but I am constantly amazed at how many people, who venture into the back country, don’t know how to properly read a map. The following article uses metric terminology but explains map reading very well.
Reading a Map
By Jon Hillis
When I ask most people if they can read a map, I get a yes response. But when I ask them where on the map we are now, I mostly get a blank expression or a few guesses here and there.
The hardest challenge people find in reading a map is how to visualize the 2D image of the map in a 3D image. In other words, how to make those lines and “green sections” look like the side of a hill with light scrub.
As with any skill, it all begins with the basics. There is no use investing in the latest and greatest technology such as a handheld GPS unit if the basics of map reading are not learned. I can’t tell you the amount of times I have been out in the field to hear “the batteries are dead”, and “I don’t know where we are, the way-point was in the GPS”.
Before anything, there are a few rules about maps:
1. Don’t draw on them with permanent markers or pens (you may need to use them again and need to be able to see features and points),
2. Try not to fold the map (this reduces the longevity of the map, causing rips and tears)
3. Waterproof your map (A wet map with running ink is about as good as a tanning salon in the desert)
There are ways of working with the above points but I won’t be covering this today.
Once you have your map spread out nice and flat, it’s time to familiarize yourself with the different parts of the map.
In this example I would like to use a 1:25,000 map. 1:25,000 basically means that for every one centimeter on the map this represents 250 meters on the ground, therefore a ratio of 1:25,000 is used. This is called the scale and is present on either the side or the rear of the map in linear (straight-line) format. You can use the linear scale with a ruler for speedy calculations of distances on the map.
There will also be a section stating the contour interval. Contours are the imaginary lines which are drawn on the map to represent certain heights at different locations. These so-called lines are used to determine the height of the terrain in the area and assist in determining rises and depressions in the land. On a 1:25,000 map the distance between contour lines represents a distance of 10 meters on the ground. You will notice with the numbers on the contour lines that some may appear to be written upside-down, this is actually an indicator of which way the land is rising and allowing you to imagine as if you were reading the number while looking up a hill. This is very helpful in planning your routes.
Contour lines are probably the most important part of locating where you are on the map. They show you ridges, saddles, peaks of mountains and open fields, all which you can use to determine where you are located. However, when you are in dense scrub or are located in amongst multiple ridges with similar features you may need to refer to further parts of the map to assist, such as the legend.
The legend, also known as the key, is a list of images representing corresponding items on the map (i.e. a long-dashed lined would represent a vehicle track). The legend covers natural items such as rivers, creeks, dams, rapids in rivers, swamp, cliffs, plus many more and also covers man-made items such as power-lines, roads, tracks, mine-shafts, jetties and much more. This section of the map is very handy in helping you position yourself on a map and gives you visual references to refer to.
You will also find magnetic declination, Datum information & the age of the map, all which come in handy when using a magnetic compass, but we will get to that once we’ve conquered map reading first!
Across the map you will find parallel lines running both North-South & East-West. These are called grid-lines and when four of these lines intersect to form a box, they create what we call a grid-square. On a 1:25,000 map each grid-square is 4cm x 4cm, which equates to 1km x 1km in distance on the ground. The lines which run North-South are called Eastings as the numbers running across the top of the map increase as they move towards to East. The lines running East-West are called Northings and the same principle applies, they increase as they go northward.
Once we locate ourselves on the map using visual referencing we can then convert this in to a grid reference. There are a few different ways we can take grid references and we really are starting to get a little ahead of ourselves so I will leave this for another time.
The goal here is to be able to pick up a map, have a look at it in 2D view and picture it in 3D view. Likewise you will get to the point where you will visualize your surroundings in 3D and convert it in to 2D to read easily and confidently on a map.
Jon is the owner of Great Explorer International, operating [http://www.outdoorgear.net.au], which focuses on offering both suitable advice and products for the Australian bush.
His skills stem from an early interest in camping and the Australian outdoors, with frequent visits to the Yarra Ranges throughout his high school years. Learning the skills necessary to survive out in varied environments through self-study and classes in both the Royal Australian Air Force and Australian Air Force Cadets, Jon focuses on passing on these invaluable lessons to those who enjoy a challenge in the great outdoors.
Currently his skills are utilized to instruct Cadets in the Australian Air Force Cadets the skills of survival and fieldcraft, amongst other specialized topics, and oversee the advice areas & product selection of his business’ web-site.
Article Source: http://EzineArticles.com/?expert=Jon_Hillis
http://EzineArticles.com/?Reading-a-Map&id=4876115
Once you are able to properly visualize your surroundings with a map, the use of a compass or a handheld GPS unit becomes much easier. When researching an area for ATV camping or hiking the proper use of a map is necessary to determine distances and terrain. Don’t get lost in the back country, learn the proper way of Reading A Map.
No related posts.
