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Basic Map Reading and Orienteering Techniques

  • Basic Map Reading and Orienteering Techniques

Map reading skills are just as important as ever for walkers and hikers despite the increased use of GPS and maps on mobile phones. If your GPS is on the fritz and you need to know how to get from point A to point B without getting lost, there’s no need to admit defeat by stopping to ask for directions. Just pull out your trusty map! Whether you’re hiking the Swiss Alps or planning a cross country road trip, knowing how to read a map is practical skill that everyone should possess. And contrary to popular belief, it isn’t particularly difficult. Once you understand what key markers like scale, longitude and latitude, and topographical lines mean, you’ll be able to travel just about anywhere with a few quick calculations.

What We need for Map Reading…???

  • Basically, we need: -
  1. The right type of map
  2. A compass
  3. pencils, eraser, and rulers.

  • Maps
  • Choosing the right type of map :-

Different kinds of maps exist for different uses. Before you can use a map to help you find your way, you’ll need to make sure you’re equipped with one that’s suitable for the type of traveling you’re doing.as examples (Road Maps, Topographical maps, Physical Maps, Political Maps, Climate Maps, Resources Maps)

A word about scales (Metric Maps)

Maps are shown in different scales (for example 1:10,000 or 1:50,000). The larger the map scale, the more detail that will be shown on the page, and the smaller the scale, the less detail will be shown. You would need to pick a map of a scale that is appropriate for what you need. Scale refers to the relationship between the size of the map and the actual size of area that is mapped, or relative distance. On a 1:10,000 scale, one of any unit on the map equals 10,000 of the same unit on the ground. Orienteering typically uses "meters" to measure distance.

The Survey Department of Sri Lanka began to prepare a map of Sri Lanka based

on metric units. for the easy and efficient use, topographic map of Sri Lanka, has been divided into 92 parts. Each part is known as a map sheet and each map sheet has been given a name and a sheet number.

A beginner's guide to understanding map scales - https://getoutside.ordnancesurvey.co.uk/guides/understanding-map-scales/

  • Reading Grid references, s, and latitude and longitude
    • Grid references

maps are covered in faint blue lines which make up a grid. Each grid square has associated numbers, and these numbers are what you use to pinpoint your location on a map. This is useful for being able to simply give others your location (e.g. mountain rescue).

Grid references, being read left to right on a map, are called eastings, and grid references going bottom to top, are called Northings.

  • Latitude and Longitude

Latitude and Longitude are global addresses, written in numbers, so that everyone can use them regardless of where they are. They are given as coordinates, made from horizontal lines, with the equator referring to 0 latitude, and vertical lines, with the line passing through the prime meridian referring to 0 longitude.

  • Contour lines

Contour lines are orange or brown squiggly lines, with numbers next to them. The lines represent the contours of the land, and the numbers tell you the height each line is above sea level. The closer together the contour lines are, the steeper the slope.

Beginner's guide to understanding map contour lines- https://getoutside.ordnancesurvey.co.uk/guides/understanding-map-contour-lines-for-beginners/

  • Compass
  • Types of compass

Know your compass.

  1. Baseplate - The mounting of the compass. Clear, so when placed on top of the map you can still see the map features
  2. Compass housing - Contains the magnetic needle and has the points of the compass printed on a circular, rotating bezel.
  3. Compass needle - Floats in liquid so it can rotate freely but without being too sensitive to movement, the red end points to magnetic north.
  4. Orienting lines - Fixed within the compass housing and designed to be aligned with the eastings on a map.
  5. Orienting arrow - Fixed within the compass housing, aligned to north on the housing. Enables conversion between grid and magnetic north.
  6. Magnetic variation - allows accurate adjustment for magnetic variation or declination
  7. Index line - Fixed beneath the rotating bezel of the compass, it marks the bearing you wish to travel along.
  8. Direction of travel arrow - Shows the direction that you want to travel along once you have taken your bearing. It is an extension of the index line.
  9. Compass scale - Displayed along the edge of the base plate so you can measure distances on maps.

Lensatic Compass (Military Grade)

ABEGINNERS GUIDE TO THE COMPASS - https://getoutside.ordnancesurvey.co.uk/guides/beginners-guide-to-the-compass/

  • How to hold a compass

Three are two methods for hold a compass.

  1. Center Hold technique

  1. Cheek Hold technique

  • Calibrate the Compass (Magnetic Declination)

It's important to remember that the compass needle is pointing to magnetic north and the grid lines are pointing to grid north.

Example of magnetic declination showing a compass needle with a "positive" (or "easterly") variation from geographic north. Ng is geographic or true north, Nm is magnetic north, and δ is magnetic declination.

Your compass needs to be adjusted for the magnetic declination (difference between the true North (pole) and the direction the magnetic needle is pointing at) There are 2 possibilities, either adjusting for true North or for the Grid North (grid direction on the map)

  1. Adjusting to True North require to align the compass Orienting lines to the edge of the map to get an accurate reading.
  2. Adjusting to Grid North require to align the compass Orienting lines to any of the vertical grid lines to get accurate reading.

your party) Understanding magnetic north -https://www.youtube.com/watch?v=oPwL0lrOdFA&feature=youtu.be&list=PLJp4yCtYcXprknSY_FAUpWG5ZbDwHmfY7

https://www.youtube.com/watch?v=oPwL0lrOdFA&feature=youtu.be

  • Direct the Map

How to Use a Compass || REI - https://www.youtube.com/watch?v=0cF0ovA3FtY

  • Bearing and Back Bearing

Fore bearing and Back bearing The bearing of a line measured in the forward direction of the survey lines is called the 'fore bearing'(F.B.) of that line. The bearing of a line measured in direction backward to the direction of the progress of survey is called the 'back bearing'(B.B.) of the line.

  • Taking Bearing with a Compass

How to take a compass bearing - https://www.youtube.com/watch?list=PLJp4yCtYcXprknSY_FAUpWG5ZbDwHmfY7&time_continue=3&v=rZd0RfsC-9I&feature=emb_title

Step 1: Line up your points

To start with you need to know where you are on the map (point A) and where you want to go to (point B).Get the map flat - a stiff map case, flat rock or your knee works. Line up point A and B with either the side of your compass or one of the black lines running down the base plate, making sure that the direction of travel arrow is point in the direction you want to go in (so towards point B).

A compass with a larger base is useful here for covering longer distances, but you can use a straight edge with a smaller compass.

For the moment, don't worry about the north arrow.

Step 2: Align to grid north

Now, hold the compass still and turn the compass housing bezel so that the “N” on the bezel and the orienteering arrow are point to grid north (the top of the map). To help do this – make sure that the orienteering lines are lined up with the easting lines on the map. Try to get this as accurate as possible - and if you have folded your map check which way is north! Again, ignore what the compass needle is doing at this stage.

Step 3: Adjust for magnetic variation

Now you need to allow for the difference between magnetic north and grid north.The adjustment varies across the country and you can generally find it printed on your map in the key. Look for 'magnetic north'. Ignore any references to 'true north' as we don't need them.Pick up your compass and turn your compass bezel anticlockwise to ADD the magnetic variation.Many compasses have a smaller scale inside the compass housing to make this easier, or use the outer scale. Most compasses only show a marker for every 2 degrees.

Step 4: Line yourself up

Now put the map away. Be careful you don't move the compass bezel.Hold the compass flat and near your body, with the big 'direction of travel' arrow pointing straight ahead. Turn yourself and the compass around slowly until the red end of the needle lines up with the orienting arrow, as in the picture.The direction of travel arrow should still point straight ahead - that's the way you are going, towards B.Look up, and pick an object in the distance that's in exactly the right direction. It could be a distinctive tree, rock, hill peak or similar. Don't use sheep, as they tend to move.Try to avoid looking at the compass all the time as you walk, as this is less accurate than using a more distant target. If you reach the target you are aiming for check the compass again, pick a new target object and carry on until you reach your next waypoint.The biggest errors by beginners here are firstly moving the bezel - it's set and should not be changed at this point. Secondly, not holding the compass pointing directly away from the body. Also, be aware of any magnets or metal near the compass: mobile phones, magnetic buttons, metal belts and similar can 'deflect' the compass needle, making it inaccurate.

How to take a compass bearing- https://www.youtube.com/watch?v=rZd0RfsC-9I&feature=youtu.be

  • A BEGINNERS GUIDE TO MEASURING DISTANCE ON A MAP

Step 1: Find your scale

First of all, you have to know your scale. If you understand the map scale number that's great, but if you find that tricky you can still measure distances accurately.

At the bottom of each map there's a scale that indicates the distance on the map. When you measure a distance on the map, just compare it to the scale, and it will instantly tell you the real world distance.

Example of a scale from an OS Explorer 1: 25 000 map

Step 2: Measuring the distance

You can measure straight line distances on a map with a ruler - there's often one included on the side of your compass. However, if you use the technique above, you can use almost anything - your pencil, fingers or a twig - to get a distance and compare it to the map scale. No maths required!

This does have one big drawback - you can only measure straight lines, which are not that common outside cities. While you could take lots of small measurements and add them up, there's an easier way using just a bit of plain old string. Try using the lanyard from your compass or a spare shoelace if you don't have a handy bit of string in your pocket.

Lay the string out along the route. You may need to use some extra fingers to pin it in place. Once you have covered the route, carefully mark the string (or just hold it in the right place) and compare it to your map scale.

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Created : Nov 25, 2019 12:29pm
Last updated : Jul 3, 2022 06:31am