Friday, October 28, 2011

Map Reading 101

A group of friends will be embarking in an ultra trail run next weekend and all of us as "urban warrior" familiar with the route from Bukit Aman to Hartamas and back would be lost in the jungle where there is no landmark to help us to navigate ourselves to the designated area.
As such, i am posting this Map Reading 101, based on my experience of being trained in Royal Military College, as an adventure racer and most importantly, as someone not being able to be in Sabah for The Most Beautiful Thing (TMBT) Trail and Ultra-Trail race.
Equipment
You will need a compass. There are a few types of compass out there actually and i am covering the most usually found and easy to use type. The concept is the same. However, make sure your compass North, points north. There has been cases where a friend bought a defective compass where his "south" was painted "north" and that render his compass to constantly points to SOUTH as NORTH. Easy to spot, if you are in the shop and you found one compass behaving differently from the others, don't buy it. There is no margin of error to be "different".
I was trained to use a lensatic compass. The military version has "Mil" as the units and the usual one sold is in degree. They are sometimes known as "Engineer Compass". If you have no choice, you can learn to use Lensatic compass like how i did.
Lensatic Compass
Don't be overly concerned about the whole setup. This compass is actually very easy to use.  It consist of the base (where the NSWE sits), the cover (the round thing you see with a gap in the middle and a wire runs across the length) and the rear, which looked like some aiming apparatus. It is not too expensive and will set you back less than RM30.
How you use this is once the direction/coordinate has been established, you use the rear sight, aimed it through the front cover, using the cable as your foresight. What you see beyond the foresight is what you should be aiming for, so you can confidently walks towards that known object before taking out the compass to "realign" your line of sight again.
The other type of compass will be the sports compass or base compass. It is a simple more easily available compass. I know Coleman sell them at about RM20. It is a good start up compass and something you won't mind losing.
Sports or Base Compass. Image taken from Silva Compass.
Base compass is easier to use and simpler. They are often called sports compass as they are extensively used for sports navigating where speed and ease of use plays a pivotal part to locate certain markers on the map.
My personal favourite is the combination compass i have that are made up of both. Call me Kiasu.
Keeping fingers cross in locating where i left this one after SAC :(
There are those Button Compass that can be attached to the wrist watch strap. They functions the same and most important is that you know the general idea how to use them to your advantage. The only setback is that they do not have the versatility to function like a full compass should a full blown navigation is needed.
I assume you have your compass with you, and for the purpose of this tutorial, i will use the only compass i have now with me, which is the Lensatic Compass. I will also do my best to show how to use the Base Compass. Map reading is not rocket science, it is common sense at best.
Knowing Your Map
A map is essentially a piece of paper with information such as, and not limited to contour (or topo), location, distance, extend of vegetation/growth, scale, North direction. A map can be as simple as a piece of paper with just a few essential information such as the North, distance, crude representation of the terrain etc. The best map available for a certain purpose is useless if the user do not know how to utilise the map or to read the map.
There is a few representation of the NORTH in a map. There is the TRUE North, the MAGNETIC North and there is the GRID North. True north usually has a STAR denoting it at the top, Magnetic north points to the magnetic pole and all compass points to this direction. It is represented as a half-headed arrow or a full allow. Grid north basically uses the vertical Gridline as the North. I am going to use the example of TMBT map as reference.
Yes, Can You Now Show Me How To Navigate?
Official Map For TMBT 2011. I Wish I Am There. Map posted with Permission from Race Director
1. Locating the North
First thing i noticed on the map was the missing NORTH. But as the Map is the official race map and having taken part in Sabah Adventure Challenge 2011, knowing the race director and what to expect, my common sense tells me that the map uses ALREADY POINT NORTH, unless you read sideway or upside down. What this meant is the vertical lines (straight line down) can be used to represent the North. So, again, the orientation of the map above is already pointing north. 
So Far So Good?
2. What's the Grid?
The STARTING point for the TMBT100KM race is at the top corner of GRID REFERENCE F12 (in Map reading/military, we call it as Golf-Romeo F- Twelve, Golf-Romeo being used to represent GR or Grid Reference). There is a missing scale on the map as well. Printing the map on an A4 paper, each grid measures 2cmx2cm.
Bring along a good ruler too for the race, if your compass doesn't have a scale.
Looking at it further, we now know that this map is a "special" map. Why is this "special"? It does not fall into the typical 1:1,000,000 or 1:500,000 or 1: 250,000 map scale. Before you start freaking out what these numbers meant, in the most simple laymen term, it shows that 1 cm or 1 inch on the map represent 1,000,000cm or 1,000,000 inches respectively. Bear in mind the smaller the last number, the bigger and more detailed the map will be.
*Update : I received a confirmation from Aman Avtar the Race Director for SAC (that organises this TMBT) that the map used is a 5km sq box. Meaning, each box in the grid represent an area of 5km square. Thanks Aman.
Taking the distance from START (GR F12) to CP1 (GR H10) to be 9.5km and dividing it over the length of  2-map square, you now know that 2cm is about 4km or 1cm is 2km. This is a 1:2,000,000 map. Understandable as the ultimate distance to be covered is 100km.
Looked like the TMBT map is made purely for one purpose only and that is to help/aid you to get from one point to anohter point. I now know why SAC Race Director decided to share the map more than a week in advance before the race - this is so you will have enough time and chances to scrutinise them. I noticed the map is very high resolution as well. Which will give good enough details to you to be utilised. So, if you have not printed out the map, it's high time to do so.
3. How Many Portion Should I Break My Maps Up?
How to print, you may want to ask. The race has a total of 11 check-point or CP Including FINISH but excl START). I would suggest that you plan to cluster your CP up in the most efficient manner. I will leave it to you reader to plan it yourself. Just remember that the less map you carry, the less confused you will be. Ensure the maps are sufficiently detailed to aid your navigation. To start with, one map for one CP will be good. You then aim to cluster them and reduce it for efficiency. Don't forget to number your map too, else, in the confusion, you might not know what map talks to which map. Ensure you have ONE whole map with you (can be up to A3) so it can be used as backup. I print my map on A4 sized paper, which sufficiently gives enough details.
4. Now Come The Fun Part.
We now know the NORTH (Map faces up) and know the estimated scale. Lets navigate from START to CP1. It would help if you have a notepad, a pencil (i suggest pencil as it works even when wet. Just make sure you bring a pocket knife to sharpen it when needed), A permanent fine tip marker (optional).
Map blown up to 600%. It is now an impressive 1:42,000 scaled map! Military map is 1:25,000, giving higher precision
a. Establish the scale on the individual printed map. This is important as it will function as a good estimated distance and duration for your navigation. When the above are printed on A4 paper, the representation has now become 9.5cm = 4km. It works out to be 1cm=0.42km. It might make sense to write down in marker pen the estimated scale.
b. Open up your compass (lensatic) or place your compass on the map (base compass)
c. Align the Map and your compass to point to the same NORTH. This is the single MOST important step. To read map correctly, you must always align your MAP NORTH with your COMPASS NORTH.
My compass north aligned with the grid line, indicating north.
Now, lets navigate to just out of the starting point, crossing the bridge using Lensatic Compass. 
If you have a base compass, you can skip this portion and scroll down.
d. Draw a straight line out from the START point as close as possible to the marked dotted blue trail. It is evidence that the you need to move directly EAST (90deg) for about 1.2km (3cmx0.42km) before taking your next or setting your next coordinates.

With that in mind, you now sight through the rear sight, turn your body until you see E or 90degree in the lense. Then you look up through the cover to locate the front sight and see what is behind the sight. That is the location you need to walk to before taking the compass out and sighting it again.

How do you know it is 1200m that you walked? It will be rough estimation again. If you noticed, the trail follows parallel to the (red) road before turning towards a populated area (black spot on map). I assume all those reading this are average athlete that has done long distance running before. With that, we all know our own pace (minutes per km) when running on the road or in the trail. A typical trail walk over rolling terrains will be about 12mins/km. Estimated this first 1.2k will be covered within 15minutes.
So far so good?
Great.
Next, will be the very long trail run towards CP1. If you look at the map, you will run into a small settlement called Kampung Mangkulat about 4km from starting point.  elevation gain, seen through the contour line (brown dotted) seems to be only 100m over the 4km distance. This is a gentle gradient that can move through pretty fast. Expect to cover the 4.5km within an hour if you WALK. Next question will be, WHERE TO WALK?
e. Draw a straight line from KM1.2 to Kg. Mangkulat. Keep the compass align like a. and b., and repeat c.
f. The estimated coordinate is now about 160deg. With that in mind, repeat the sighting again and keep moving towards that coordinate.

For better accuracy, you need to really plan in details the route you will take. Noticed in the TMBT map, the route to CP1 is mainly running parallel with the (red) road. That road could be an unpaved road or even logging road.This is when your preplanning before the race come into play.
If you plan properly, your notebook now should look like this:
To CP1
1. Starting point -cross bridge - 1.2km :90deg
2. 1.2km - Kg. Mangkulat - 4km :160deg
3. Kg Mangkulat - GR H11(end of red road) - 3.0km : 160deg
4. GR H11 to about 800m EAST : 90deg
5. 800m SOUTH :180deg
6. 1.2km :240deg.
(*this is just an estimated example, use only as a guidance).
Getting to CP1 on a base compass.
Base compass is easier to use compared to lensatic compass. It is really a matter of preference, which is why the compass i have functions as both. Base compass has an outer bezel than can be turned/moved 360degree. The principle of action is same as lensatic compass, just more simplified. As i do not have a base compass with me, i am using graphical representation to show how that is done.
Lets Start Using Base Compass.
To use the base compass, repeat step a. b. and c. above.
Align the Map North with the Compass North.

Next align the edge of the compass to the direction you want to go. The North of the compass MUST continue to point North. This way, the MAP remains to be orientated.
d. Once you complete the above, it is time to turn the outer bezel and align the bezel N(orth) with the needle and the map.
When you do that, you are essentially "automatically" setting the coordinate. In this case, the EAST or 90degree will be at the "Direction Arrow".
e. You can now remove the compass and use it. You need to keep the compass at your waist level, with your hand close to your body. You will then continue to TURN your BODY until the compass NEEDLE align with the DIRECTION ARROW.
If you noticed, the OUTER BEZEL N remains where it is. On a proper compass (i.e. not the one i drew as an imaginery one), you will notice that the coordinate is also 90Deg on the outer bezel or points to E(ast). Simply look up and see what is infront of you, walks towards it and check your line of sight again per step e.
Per lensatic compass, do your homework before the race and write in your notebook how you plan to use these information.
So How Now?
The usage of compass is a basic mean of navigation. With lensatic or base compass, the basic principle remains the same. You have to establish and align the MAP and COMPASS with NORTH. Then work to obtain the coordinate/degree of where you want to go. It is important to keep the coordinate/degree correct, as that is your LIFELINE. Say if you are not sure where you are, and out of some luck, you twisted the outer bezel of the base compass and now you are NOT sure where you are supposed to be heading. Setting the outer bezel coordinate/degree to align with the DIRECTION ARROW will almost ensure you get back right on track.
I sometimes get really anal and hum the coordinate in my head as i navigate through.
"160degree. 160degree. Check. 160degree. 160degree"
TMBT is a "controlled" race in the sense that the route are made known and the map shared prior to the race. Each participants are responsible to do their own homework and ensure that they practice as much as they can with their compass to get familiarized.
Once you are familiar with the basic principle, you can be like me, able to use whichever type of compass to help navigate through the terrain and map.
After reading this simple tutorial, i hope i make it a little easier for all of you To Do It Like A Man.
*I am available for practical if you are really not sure, just email me and i will see what i can do to help. A Cup of Kopi O Kosong can be used to barter trade this skill.

13 comments:

  1. great article. reminded me on my St John ambulance day in my school where we learn map reading.

    still own the sport compass till now.

    I will go get a lensatic compass and join your practical session.

    1 pint of Guinness with your name on it waiting for u. :)

    ReplyDelete
  2. Bro - sharing what i can and WHILE i can. ;) No point kedekut ilmu right. I enjoy teaching and showing actually. Just wished i had more time to write more.

    Lensatic compass? u interested in the one i use? combo of Lensatic and Sports :) Can be arranged!

    As for guiness...i dun drink lah...will exchange for a bottle of water. :)

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  3. Aiyo .. need to re-read and do some practical later but I have the same compass that you've misplaced lol. Errm dont ask me about what compass, I just know where North is :)

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  4. Wow! Brings back ole times from my school days...

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  5. Yimster - as long as u dont keep going NORTH. :)

    Paul - now u felt like 16 again? ;)

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  6. Thanks for the great refresher! Bookmarked so I can practice orienteering next time.

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  7. Paviter - thanks for dropping by!

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  8. wow.. a practical one indeed ! love the step by step details.. thanks for sharing bro !

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  9. Some map reading would come in handy at Bukit Kiara, to learn where is where in terms of areas under threat of development. Navigating through thick forest is difficult and easy to get disoriented. Well or at least staying on the trails makes a compass not necessary. Thanks for the tips.

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    Replies
    1. I so agree. Why need a compass in Kiara unless the whole place has been destroyed beyond recognition.

      Or have i spoken too soon?

      Delete

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