Estimation

ESTAMATION

Estimation means ‘approximates guessing’. Estimating the distance/ widths is one of the conditions for Dwitiya Sopan Scout/Guide. This estimation should be done without apparatus with 25 percent error. This means that the Scout/Guide should be so conversant with these estimations that he can guess them correctly. He can do so only if he gives him/her self plenty of training.

JUDGING DISTANCES:

Know the exact length of your pace, use it for measuring the distances and widths.
Where you cannot walk and measure you will have to guess the distance. Some ideas are given here.
Remember things can appear nearer or further than they really are depending on how clearly you can see the outline. Also, if there is water between you and object, the distance can be deceptive.
Objects seen further away:

  • when they are in the shade,
  • Across a valley,
  • When they are the same color as the background,
  • In a heat haze,
  • When you are lying down or kneeling.

Objects seem closer:

  • With the sun behind you,
  • In very clear air,
  • When a different color from the background,
  • When the ground is fiat (or snow covered),
  • When it is larger than other objects nearby,
  • When you are looking across water, or a deep valley.

Visible objects seen nearer at night than during the day.

Remember the eye measures distance “as the crow flies”, and does not allow for uneven terrain. In other words actual distance may be greater than visual distance.
Examples:

  • At 700 meters a person look like a post.
  • At 650 meters the head is not yet visible.
  • At 550 meters the head is visible as a dot.
  • At 450 meters a person appears bottle shaped.
  • At 350 meters movement of the legs can be seen.
  • At 250 meters the face can be seen.
  • At 200 meters details of clothing are recognizable.
  • At 100 meters eyes and mouth can be seen clearly.

LEARNING TO JUDGE DISTANCE

As a means of checking your estimates, learn the exact length of your pace. If fairly tall, learn to pace an exact meter, heel to heel. On a quiet road, in a field, or out on the prairie, begin judging short distances to various objects, then pacing to check your “guess.” Gradually increase the distances. Do this in competition with several other Scout/Guide and you’ll find it an interesting game. Remember that the eye measures distance as in an “air line,” from eye to object, and does not allow for irregularities of the ground. In other words, ground distance may be greater than visual distance.

JUDGING DISTANCE BY SOUND

Distance can sometimes be judged by sight and sound. If you see a gun fired, for instance, you can tell how far the sound has come, if you remember that sound travels at 365 yards a second.
During a thunder and lightning storm you may be able to quiet nervous people by pointing  out to them the time between the flash of lightning and the roll, or crash of a bolt – this proving that the bolt in reality struck several miles away.

WIDTHS

MEASURING WIDTHS:-

Napoleon Method Stand on one shore of a stream. Bow your head, chin against your chest. Hold your hand to your forehead in a salute. Move your hand down until the front edge of it seems to touch the opposite shore. without changing the position of your hand, make a quarter turn. Notice the point at which the edge of your hand seems to touch the near shore. Pace off the distance to that point and you will know the width of the river. Napoleon might have used the brim of this hat instead of his hand. If you are wearing a cap with a visor, so can you.

MEASURING WIDTHS – STRIDE OR STEP METHOD:-

Select an object on the opposite side of the river, such as a tree and we mark it as A. Mark the point directly in front of the object on the opposite side of the river, mark it as point Betake at least 50 paces to point C, so as to form line BC. Note that line BC should be perpendicular to line AB. Mark point C with a stick or another person. Again, pace another distance to point D. The distance CD is half the distance of BC. From point D, pace another distance to point E. Line DE is parallel to line AB. Point E is marked on a location wherein you can see point forming a straight line with point A. meaning when you look at the stick on point C. It somewhat blocks your line of sight to point A. The distance AB is twice the distance DE. AB = DE x 2. We can alter the method a bit. Instead of having distance CD half of distance between BC, we can make it equal to each other. Do the same method to find point E. Using this alternative, AB = “DC”. This is more accurate.

TRIANGULATION METHOD:-

A is a position where you are standing. X is a object on another side of the river bank. Take 6 or 10 more more steps on any side say towards C (Imaginary point). Halt at B i.e. middle of the A-C. At B, put one staves or another Scout/Guide may stand. Walk up to i.e. equal steps of AB. For Example if you have walked 10steps from A to B. Then walk 10 more steps from B toward C. From C, walk on opposition direction up to the place where you will found B and X in same line. Marked that point  as D. Distance from C to D is the Distance/ Width of the River i.e. AX

NAPOLEON METHOD

Stand on one shore. Bend your head, chin against chest. Hold your hand to your forehead, palm down. Move hand down until the front edge of it seems to touch the opposite shore. Now make half right turn distance to the point which the edge of your hand seems to touch is the width of the river, place it. Napoleon would have used the brim of his hat instead of his hand. So would you if you had on a broad-brim Scout/Guide hat.

COMPASS METHOD

Stand on the one side of a river (B) notice a rock or object exactly opposite to you on the other side of the river (A). point the travel direction arrow of your compass at the rock.
Turn the dial until the compass needle lies over the orienting arrow, north point pointing N. Read the degrees (in this case 120) Add 45 (making if 165). Walk along the river pointing the travel arrow toward A. when the compass is oriented, stop . Distance CB is the width of the river.

SELF MEASUREMENTS

For estimation the distances or widths your Scout/Guide will have to know your self measurements. As given below.
As an aid in making short measurement you should know a number of your personal measurements. Your known hand-span will often be particularly useful.
If fully developed your measurements will be close to this:

  • Breadth of thumb, and nail joint of forefinger = 1 inch (2.54 centimeters).
  • Span of the thumb and forefinger = 6.5″ (or 17centimeters).
  • Span of thumb and any other finger = 8.5″ (or 21.6 centimeters).
  • Wrist to elbow = 10″ (or 25 centimeters).
  • Elbow to tip of forefinger = 17″ (or 43 centimeters).
  • Your reach, arms out-stretched, will nearly equal your height.