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CHAPTER 01

INTRODUCTION TO GRID MAPS

INTRODACTION TO MILITARY MAPS AND TYPES OF MAPS

GENARAL

1. As a soldier very often we have to operate unfamiliar areas .The quickest and the best to study

and understand such and area is by referring to map of that area your familiarization with ground will always depend on your ability to read and understand the map of that area.

a. Awareness of location.

b. Studying and unknown area without actually visit it.

c. To measure distance

d. To travel from one area to another.

e. Finding out the actual location to another.

f. To obtain fire support in a military operation.

g. To inform the owns location to another.

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CHAPTER 02

TYPES OF MAP

1. Basically there are two types of maps.

a. Topographical Maps: Topographical maps show in a as much detail as the scale allows, both physical features of the ground – rivers, woods, and hills with their height and shapes – and the

manmade features – roads, railways, towns and building etc. They also contain a large no names both specific names of towns, villages and rivers, and also descriptive names of generally features such as

post office, hospital etc, Their purpose into present a picture of the ground as it exists.

Topographical maps may vary in scale from about 1:10000 to about 1: 250000. Following are most commonly in use.

(1) One inch to one mile (1:63360)

(2) 1: 25000. (3) 1: 50000

b. Thematic Maps: Maps which are drawn on a particular theme/ topic giving more

information on that theme.

Ex. Rain fall, natural forestation, population, road maps, agricultural map,naval map, arial map.

AIR PHOTOGRAPHS

2. These are very accurate and reliable but it’s too difficult to interpret. A special training and equipment’s are necessary to interpret aerial photographs accurately.

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CHAPTER 03

MAP MARGINAL INFORMATION & CONVENTIONAL SIGNS

1. Detail is the world normally used to cover all information appearing on the body of a map other

than names descriptions, figures grids, and the method of showing relief. It thus comprises all line work (other than contours), symbols and conventional signs, by which both natural and artificial features are

shown.

TYPES OF DETAIL

2. The following are the general types of detail:

a. Towns, villages and buildings. b. Natural features, including vegetation

c. Communications. (Roads, Railways etc) d. Miscellaneous artificial detail (buildings)

e. Boundaries.

USE OF COLOURS

3. The use of different colours is a major means of showing and distinguishing detail of any or all

of the types of details of a map. As there are conventions for symbols, there are similarly conventions for colours. Unless governed by international agreements, these colour conventions are not binding, but they

are well established by used and are normally followed.

The following colours are normally used as indicated:

Blue : Water, marsh, permanent ice and snow features.

Black : Outlines of all artificial detail, rocks and cliffs on the coast.

Red : Main roads, sometimes buildings.

Green : Woods, Vegetation

Brown : Contours, sand minor roads etc.

Yellow: Minor roads

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MARGINAL INFORMATION

4. All the details needed to read a map is given in the area of paper surrounding the map. This area is called as the margin of the map. The user must be competent with the information in order to read the

map correctly.

5. The information given in the margins of military maps are produced under an agreement (between the user and the organization that draws the map). To a large extent this information is

standardized so that the user will know where to look for the information he needs. It is important to keep in mind not all maps and the information given in their margins are standardized.

6. Following are the information given in the margins of the Sri Lanka 1.50000 map presently used

in the SLAF. (Please note that the alphabetical letters used in the paragraphs below correspond to the alphabetical letter used in figure)

7. Lay out as follow:

a. The Country and the Scale of the map.

b. The top center gives the title of the map sheet. It is usually the name of a widely known prominent / largest city or town that is shown the map. This is also called the sheet name.

c. The top right corner gives the sheet number of the map. For military purposes map

are referred by the sheet number and not the title.

b. c.

i

j.

Gr

ad

ua

te

d

li

ne

s

(g

e

e. d.

a

f. g. h.

k.

Gr

ad

ua

te

d

li

ne

s

(

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d. The symbols (including the description) that are used to represent on the map, the 'details'

that are available on ground are indicted at the bottom margin. These details are categorized under the headings boundaries, roads and paths, railways, drainage, vegetation and general

features. These details occupy the area from center to the right corner of the bottom margin this is called the 'legend' or the 'key'.

e. The administrative Index which gives information in diagrammatic form of the various

administrative boundaries those are relevant to the map.

f. Details of compilation (of the respective map) are indicated.

g. The location of the actual map in relation to the adjoining map sheets is indicated at the lower margin. (In diagrammatic from) details of the origin of the grid system is indicated below

this diagram.

h. The graphic/ linear indicated of the direction of north points. (True North, Magnetic North & Grid North) The variations (in degrees) between the different north points are also

indicated. The Mean Magnetic variation (with the year of measurement) is indicated above the diagram. The annual change and the position of the grid convergence and declination on the

respective map sheet is indicated below the diagram. This diagram is known as the declination diagram.

j. Graduated lines (generally known as the ‘bar scales’) that are required for the

purpose of measuring distance on the map are indicated at bottom left. The top line is graduated scale in kilometers and the lower line is graduated in miles.

k. The system of projection used / adopted to draw the map and the contour interval used

throughout the map and the map datum with the unit used to measure the elevation.

l. Under what authority the map was published.

CONVENTIONAL SIGNS

8. Almost everything that appears on a map except a written name is a conventional sign it is

important to remember that conventional signs are meant to be memorized but to learn them by practice would be of an advantage to the user.

9. Conventional signs are designed to enable the maximum amount of information available on the

ground, to be indicated on a map in the clearest possible way. These objects which are shown on the map are appearing on ground but by the use of a simple symbol to which we refer to as a conventional

signs. Most conventional signs are quite obvious. Whatever the conventional sign or the colour may be, the meaning of it is always indicated in the margin of the map. Hence it is important to study the

marginal information and refer to same as and when required.

10. For military purposes, in order to indicate military details on a map a different set of symbols are used. These symbols are given in annex 'A' to this précis.

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DESCRIPTIONS

11. Where no conventional sign or other type of symbol is considered appropriate, items of interest a importance may be provided by words or figures according to the purpose of the map eg, bridge

classification.

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CHAPTER 04

CONTOURS

01. A contour line is a line on the map points of equal heights, above mean sea level. This is the

standard method of showing relief on topographical maps. Contouring combines on accurate indication of height with a good indication of shape

CHARACTERISTICS OF CONTOURS

a. Contours are shown at a regular vertical interval.

b. Usually drawn in brown.

c. Every fifth contour in darker in colour and thicker (These are known as index

contours)

d. All points are at the same height above means sea level.

e. Every contour line closes on itself (contours are continuous. How ever far they seen,

they must in the end return to their starting points)

f. Contours do not cross each other. (Only exception is when a contour runs into a cliff).

g. When the spacing of contours down a slope gets closer together at the bottom, the slope is convex. Convex slopes mean short visibility and fields of fire: dead ground comes close.

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h. When the spacing of the contours gets further apart at the bottom, the slope is

concave .This gives long visibility.

j. Meandering contours varying distances apart but never very close mean undulating ground.

k. Triangular and closely spaced contours indicate smooth slopes.

l. Contours always run up rivers and streams. The shaper the angle at which the

contours turn on the stream the steeper the slops on the sides.

UNIFORM, GENTLE SLOPE

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UNIFORM STEEP SLOPE

CONCAVE SLOPE

CONVEX SLOPE

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RIDGE

HILL

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SADDLE

VALLEY

DEPRESSION

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SPUR

DRAW

CLIFF

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CUT & FILL

GRADIENT

02. Gradient is the angle the ground makes with the horizontal level (of the ground). It may also be referred to as the steepness of the slope. That is to see how much of horizontal distance needs to be

traveled in order to gain the height of one foot

03. The requirement of the gradient is to know if the ground (for example a road) is

too steep for a certain type of vehicle to move.

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a. Measure the HD between two contours as accurately as possible.

b. Check the VI of the contours.

c. Apply these data to the formula given below.

VERTICAL INTERVAL (VI)

HORIZONTAL DISTANCE (HD)

(Note: The HD is measured as per the scale. The VI is always given in the map.)

Example: Suppose the HD is 120 yards and the VI (of the contours) is 50 feet;

On this particular bit of ground there is a rise of 50 feet in a distance of 120 yards (or 120x3 = 360 feet).

Therefore, the ground rises 1 foot in 50 feet

360

The gradient is 1 in 7.2 or 1:72

(Note : If it is difficult to measure the HD between two contours due to their closeness, provided that the slope is uniform, it is better to take a distance over several evenly spaced contours the measuring

same is easier.)

Example 2 : Suppose the VI of a particular map is 20 meters and the HD between four evenly spaced contours is 1050 meters;

As there are three (3) spaces between four contour lines the VI now would be 20 meters x

3 = 60 meters.

On the particular bit of ground there is a rise of 60 meters in a distance of 1050 meters.

Therefore, the ground rises 1 meter in 60 meters. 1050

Hence, the gradient is 1 in 17.5 or 1:17.5

= GRADIENT

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CHAPTER 05

GRID REFERENCES AND GRID SYSTEM

01. It is required to differentiate one point (on the map) from the others in order to identify and mark

each point for military purposes. To do this there is a simple but accurate way, an imaginary grid system is used.

THE GRID SYSTEM.

02. A grid system is a rectangular system of lines with which any point can be defined and located by

a reference to the lines that make up the square within which the point falls into.

03. The originating point of the drawing of the grid network for Sri Lanka is located in an unknown

position of the Indian Ocean which is selected from 200,000 meters East and South of the mountPidurutalagala.

04. Maps are usually printed so that the north is approximately at the top of the sheet when the writing (on the map) is the right way up. Hence, the grid lines are drawn so one set of lines run

approximately from north to south (vertical) and the second set of lines run approximately from west to east (horizontal).

200,000m

200,000 m

‘0’ point

Pidurutalagala

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EASTING & NORTHING

05. The lines running north to south and east West are known as Easting and Nothings.

EASTING: Lines

06. running north to south and value increasing towards east are known as Easting. (Vertical Lines)

NORTHING:

07. lines running west to East and value increasing towards North are known as nothings.(Horizontal

lines)

08. All easting and northing are originated at a South West Corner of the Grid system (Square).

PURPOSE OF GRID SYSTEM

a. To provide a reference system.

b. To provide a rectangular frame work (within which all control points are computed and plotted in rectangular coordinates thus simplifying the calculation for bearings and

distances.

c. To simplify the layout of standard sheets and for joining of adjoining sheets when necessary.

TYPES OF GRID REFERENCE

09. There are different types of grid references used by the military.

a. Four figure GR - 1000 x1000 Yards/Meters b. Six figure GR - 100 x 100 Yards/Meters

c. Eight figure GR - 10 x 10 Yards/Meters

ACCURACY

10. By giving a four figure GR, a point within that particular grid square can be located. But when

there are two points which have the same symbol (Eg. Two temples) in the same grid square to pin point the object a six figure GR has to be given. For Artillery and Air- Force (For air drops)an eight figure GR

has to be given to make it more accurate.

11 Position of each point within – square is indicated by its distance east of the original (zero) north

south line first and followed by the distance north of the original (zero) west – east line. In other words the easting comes first and is followed by the northing. The numerical value thus obtained is called

the grid reference (GR) of the particular point.

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FOUR FIGURE GRID REFERENCE.

12. The GR of the point reflects the GR of the square in which the points/s is/are found and the numerical values of the lines are those that from the west and south sides of the square.

4 figure GR 45 46 47 48

4511

12

11

10

09

4 Figures GR

4609

SIX FIGURE GRID REFERENCE

13. In order to be more accurate especially if several points that need to be referred to fall in one square, it would not be sufficient to give the reference of the square but would need to indicate exact

point/s within the square.

14. To provide an accurate grid reference to a point of detail it is necessary to break-up the square shown on the map into ten sub divisions in each direction.

15. The following points are to be remembered.

a. A device known as the 'roomer' is used to divide the grid square/s to 100m smaller squares.

b. A GR always has six digits.

c. If a line is numbered '00' the ciphers must be included in the distances

east and north measured from it.

A

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Six Figure Grid Ref

45 46 47

452107

Six figure Grid Ref 457104

10

09

Six figure GR 450101

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CHAPTER 06

INTRO TO COMPASS/ SERVICE PROTRACTOR

DESCRIPTION

01. The Silva compass calibrated in mile and in degrees. It’s design is based on the light weight compass originally introduced for orientating and it is in many aspects easier and more convenient to use

than prismatic compass for cross country exercises. There are several types of light weight compass different in many aspects. The diagram of a Silva Compass is as follows.

Features of the Compass

a. - `U’ cut b. - Lid c. - Mirror d. - Hair line

e. - Hinge f .-Luminous patch (zero mark, Index painter) g. - Transparent base plate h. - Compass dial (circle in degrees)

i. - Base line arrow (orienting arrow) j. - Compass needle k. - Scale l. - Base line

m. - Luminous patch n. - Locking catch o. - Compass sling p. - Scale - mm/ inch

q. - Rubber shoe

WEST 270

N

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02. The compass is mounted on a transparent base plate and could be closed with lid when not using.

In that a scale in millimeters/ inches is given to measures the distance in the map.

03. The compass needles are white at the south end and red with a luminous patch at the north end. The outer circle is graduated in two degree divisions from 0 – 360 (or circle is graduated in 50 mils

divisions from 0 to 6400 mils. The circle can be rotated by hand orienting arrow in the center always points to 0 on the dial. Always the bearings are read from the value shown against the index pointer on

the dial.

USE OF SERVICE PROTRACTOR

DIRECTIONS 1. NORTH

2. SOUTH 3. EAST

4. WEST

04 When a protector is used to plot a bearing, a North South line parallel to the grid must first be drawn thought the point from which the bearing is to be plotted.

05 The protractor is then placed with its zero line on this North – South line, and with the centre point

of the zero line from the point from which between 0 and 180 degrees .So that it lies on the East side of the North South line , and the bearing to be plotted will be read on the outer line of figures .If the

bearing falls between 180-360 the protector must be placed on the west side of the North South line and the bearing will be read on the inner line of figures.

NORTH

BEARING ANGLE

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CHAPTER 07

DIRECTIONS AND BEARINGS

POINT OF THE COMPASS

01. Out of the 32 points in the compass, only 16 shown in the diagram are generally used. These are the 4 cardinal points, (namely North [N], South [S], East [E] and West [W] and the 12 intermediate

Points.

02. The letters N, S, E and W are combined to make up the names of intermediate points.

Example : SE stands for South East NNW stands for North West

(North of North West)

The degree System

03. The circle is divided into 360 degrees. Zero (000) being at the N (point). The four quadrants of

the circle are each 090 degrees. Hence, E, S and W points fall at 090 degrees, 180 degrees and 270 degrees respectively.

04. Each degree is sub-divided into 60 'minutes' and each minute is further divided into 60 'seconds'.

However these sub-division are not used for reading/navigational purposes (at this level).

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05. An elevated 'o' symbol is used to represent 'degree'.

BEARINGS

06. A bearing is the angle that a line makes with a fixed zero line and is always measured clockwise.

The zero line always north, unless some other zero line is stated.

a. Example 1: If one were to stand at point 'P' looking in the direction of point 'A', the bearing

of point 'A' would be the angle between the north south running through point 'P' and the drawn from point 'P' to point 'A', measured clockwise.

N

A

045°

P

b. Example 2 :

If one were to stand at point 'P' looking in the direction of point 'B', the bearing

of point 'P' would be the angle between the north south running through point 'P' and the line drawn from point 'P' to point 'B', measured clockwise.

A bearing (angle) measured clockwise from the point of observation is called a

'forward' bearing.

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(1). Example 1 :

With reference to the above diagram ….. The forward bearing of

point 'A' is ………….

(2). Example 2 :

With reference to the above diagram ….. The forward bearing of point 'B' is ………….

07. The bearing (angle) to the point of observation from the point being observed (measured

clockwise [from the point being observed] with reference to the north – south line running through the point being observed) is called a 'back bearing'.

(1). Example 1 : With reference to the above diagram …..….. The forward

bearing of point 'A' is ………….

(2). Example 2 : With reference to the above diagram …..….. The forward

bearing of point 'B' is ………….

d. The difference between a forward bearing and its back bearing is 180 degrees. Therefore the following formula is to be used in order to convert a forward bearing to its back bearing and vis-à-vis.

(1). If the value of the forward bearing is less than 180 degrees, add

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(+/plus) 180 degrees to the value.

Example : Suppose the forward bearing to an object is 95 degrees.

As this value is less than 180 degrees the value of the back bearing would be;

95 degrees + 180 degrees = 275 degrees

(2). If the value of the forward bearing is less than 180 degrees,

subtract (-/ Minus) 180 degrees to the value.

Example: Suppose the forward bearing to an object is 248 degrees.

As this value is more than 180 degrees the value of the back bearing would be;

248 degrees - 180 degrees = 68 degrees

08. Plotting Grid Bearings

a. Plotting grid bearings is done using a protractor.

b. When the protractor is used to plot a bearing on the map, the following steps are to be followed.

(1). A north-south line must be drawn parallel to the grid lines through the 'point' from which the bearing is to be plotted.

(2). The protractor is to be placed with its zero line (the line indicating 000

degrees or 360 degrees) on this north-south line, with the center point of the zero line on the point from which the bearing needs to be plotted.

(3). Make a 'mark' on the map as per the numerical value of the bearing

(Measured clock wise from the north) to be plotted and remove the plotter.

(4). Draw a line from the 'point' from which the bearing was required to be plotted to the 'mark' made on the map.

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09. Reading Grid Bearings.

a. Reading (measuring) grid bearings is done by a protractor.

b. When the protractor is used to measure a bearing on the map, the following steps are to

be followed.

(1). Place the protractor with the zero line (of the protractor) along any north- south grid line which is 'cut' by the line of which the bearing is required to be

measured.

(2). Read the numerical value of the grid bearing off the protractor point at which the line (of which the bearing is required to be measured) tallies with the

markings of the protractor.

10. Plotting And Reading True And Magnetic Bearings

a. All bearing on a map are plotted as grid bearings.

b. In order to plot a true bearing or a magnetic bearing, it is absolutely necessary to

convert them to grid bearings.

90 EAST

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11 Conversion of Bearings

a. To convert a bearing of one sort to another (for example a magnetic bearing to a grid

bearing) it is necessary to add (+) or subtract (-) the appropriate angle between the north points concerned.

Example : What would the value of the grid bearing be if the value of the magnetic

bearing is 243 degrees (Consider the Grid Magnetic angle to be 003

degrees west [of the north- south grid line/s] and that the annual

magnetic change is negligible.)

Grid bearing = Magnetic bearing – Grid Magnetic

Angle

= 243 – 003

= 240 degrees

b. The required information for this purpose is always indicated in the margin of the map.

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CHAPTER 08

MAGNETIC VARIATION

North Points

a. In the study of map reading three types of north points are referred to. They are as follows.

(1). True North.

The earth spins on a axis which passes through the north and south poles. The north pole is the geographical north or the 'true north' of the earth.

Meridians are imaginary lines 'drawn' from North Pole to South Pole and the true north – south lines.

(2). Magnetic North.

A compass needle does not point in the direction of the North Pole. Hence, it does not indicate the true north. It points to a place in the far north of Canada

which is known as the 'magnetic north'. The position of the magnetic north changes with time.

(3). Grid North.

The direction of the north – south grid lines is recognized as the grid north. The grid north of any given point on the map is the north – south line

running across the respective point. Since all grid are parallel and since they are drawn on the map, it is vary convenient to use them for drawing or

plotting bearings.

b. It is important to remember to mention the type of north (true, magnetic or grid) being referred to.

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c. When bearings are taken from true north it is referred to as a true bearing.

Similarly bearings taken from the magnetic north are referred to as magnetic bearing and those that are taken from the grid north as grid bearing. When bearings are given it is important to

mention the type of bearing. (Whether it is a true bearing , magnetic bearing or a grid bearing )

d. It is important to remember the following.

(1). The angle between the grid north and the magnetic north is the grid magnetic angle.

(2). The angle between the grid north and the true north is called the grid

convergence.

(3). The angle between the true north and the magnetic north is called the magnetic declination.

(4). The magnetic pole varies its position. Hence the grid magnetic angle

is affected. The amount by which the grid magnetic angle changes annually is called the annual magnetic change.

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CHAPTER 09

MAP SETTING (ORIENTATION)

01. Setting a map means turning the map so that direction of 'details' on the ground corresponds with the same directions (of the same details) on the map. This is also called as orientating the map.

02. There are three basic methods or setting a map. They are;

a. By inspection (of the surrounding details). b. By setting in relation to the north.

c. By the use of a compass.

03. Setting A Map By Inspection

a. This is the simple and quickest way of setting a map. However in order to set the map successfully one must have a good idea/knowledge of (his or her) own position.

b. Using this knowledge, the map has to be turned until the features (details) on ground tally

with the details shown on the map.

c. When the map is set, the details that are found to be ahead of the own position as per the map will be found to be in front of the observer on the ground. Similarly. The details that are

found to be behind the own position as per the map will be found to be the rear of the observer on the ground.

Example 1 : If you are on a straight road, line up the road on the map with the

road on the ground, pointing in the right direction. This can also be done at cross roads.

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Example 2: If you are on a road, or is on road which is not straight and you cannot identify the bends, it is necessary to locate other 'objects' whose direction

you can check in relation to your own position and rotate the map until the directions to (the) objects that are on the ground tallies with the

directions as indicates on the map.

Example 3 : In open hilly ground one has to rely on the shape of the ground and the corresponding positions of the contours.

04. Setting A Map in Relation To The North

a. The north should be determined by studying the movement of the sun. The north on the map must now be turned to correspond with actual direction of north.

05. Setting a Map by The Use Of a Compass

a. This is the most accurate method of setting a map.

b. Set the value of the grid magnetic angle on the compass. (If the magnetic declination is to the west of grid north. If same is to east of grid north, it has be set in the reverse. )

c. Place the compass on the map so that the direction of the travel arrow coincides with

the north direction of a grid line.

d. Rotate / twist the map along with the compass until the compass needles coincides with the north point of the circle (the 000 degree mark.)

e. The map is now set with the grid lines pointing to grid north.

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CHAPTER 10

TAKING A GRID BEARING FROM A MAP

06. To take a grid bearing from a map the compass can be used as a protector, ignoring the compass needle. To read the grid bearing from A to B, place the compass with alongside on the line AB and with

the line of the index pointer pointing towards B. Then turn the graduated circle so that the orienting arrow points towards grid . North and the base lines are parallel to the north – south grid lines. The grid

bearing of B from A is then read by the compass dial at the index point.

TAKING MAGNETIC BEARING (Bering to ground features)

07. To take a magnetic bearing on the ground hold the compass horizontally and point the direction

of the index pointer at the object. Then while keeping the compass in this position, turn the graduated circle so that the orienting arrow corresponds with the north (red) end of the needle. The magnetic

bearing is then read at the index point subject to correction for the individual error (Compass error). In this movement the hair line must cross the index pointer.

MARCHING ON A BEARING

08. To march on a bearing (required bearing) convert the grid bearing to its equivalent magnetic bearing as described. Set the graduated circle to read this magnetic bearing at the index pointer. Then

turn with the compass until the north end of the needle coincides with the orienting arrow. While holding the compass in front of you march in the direction of the line of bearing, as long as the compass needle

and the north arrow are kept coincides. If so the direction of sight will remain on the required bearing.

0/360

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DEFINITIONS OF NORTH

09 Directors are measured by bearings and that bearings are the angles measured clockwise from a zero line which is normally the direction of the North. There are however three types of north, each of

which differs by a small amount. These are: a. True North.

b. Grid North. c. Magnetic North.

TRUE NORTH

10. True north is the direction of the North Pole. On a map the direction of true north is shown by the lines of longitude (Meridians). Bearings measured from True North are called true bearing. These are not

normally used by map readers.

GRID NORTH

11. Grid north is the northern direction of the north – south grid lines on a map. A grid system being

a rectangular system imposed on a curved surface cannot exactly fine the lines of longitude and latitude. There is therefore, except along the standard meridian on which the grid is based, a small angle between

the direction of grid North and True north. This angle increases with the distance east or west from the standard meridian. The grid lines on a map provide the most useful and normal reference for measuring

bearing on a map. Such bearings measured from grid North are called grid bearings. These are the bearings most commonly used in Map readings.

MAGNETIC NORTH

12. Magnetic North is the direction in which a compass needle points when free from error on

disturbance. The direction is to the magnetic pole which differs from the North pole: its position varies slightly from year to year. Bearings measured from magnetic north are called grid bearings. These are

the bearings read on a magnetic compass, subject to its individual error.

ANGLES BETWEEN NORTH POINTS

a. Magnetic declination - The angle between magnetic and true north at any point. b. Grid Convergence - The angle between Grid North and True north.

c. Grid Magnetic angle - The angle between grid north and magnetic north. This is the angle required for conversion of magnetic bearings to grid bearings on vice versa.

(Grid magnetic angle - 2.80 3

0)

Method of orienting a map

13. There are two methods of orientating a map 1. By inspection the surrounding detail

2. By setting on the north point

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Setting a map by inspection

• This is the simplest and quickest way of setting a map provided you must have some idea of

your own position.

• If you are on a straight road line up the road out the map with the road on the ground pointing in

the right ,at a cross road the map can beset similarly

FINDING POSITION FROM LOCAL DETAIL

14. In the normal case where you know your approximate position but wish to pin point it more accurately, and where there is local detail marked on the map identify at last two difficult points as a

close to you as possible and preferabaly at right angles to each other in direction .Keeping the map correctly orientad,as initially determind,mark the diarection of your own position from each point and

note where these inter sect.That should be your positon check sighting on a third point in a different diarection, and confirm by the approximate distance. On a hilly ground the contours will help

determining your position.

Finding your position

• Set map(ORIANT) with compass.

• Select 3 permanent futures or objects on the ground hilltops buildings(these object should be mark on the map)

• Object must be different direction.

• Take compass forward bearings to each of these objects. Convert these forward bearings in to

back bearing.

• The center of the triangle is your own position.

Finding the position distant object or enemy location (intersection)

• Set the map

• Take up two points which you can identify on the map and ground.

• Take forward bearing From those two point

• That bearing concert to map bearing..

• That map bearing plot on the map.

• The place in which in two lines cut is the object.

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CHAPTER 11

BY PASSING AN OBSTACLE

INTRODUCTION

01. The quicker and better you can cross obstacles in battle, the less likely you are to be seen and shot while doing it. This requires practice and teamwork.

AIM

02. To teach Cadet’s how to get over obstacles. As individuals or as member of a fire section.

TYPES OF OBSTACLES

03. a. Water Obst

a. Wire Obst b. Walks, ditches & gaps otc

c. Minefields.

HOW TO CROSS OBSTACLES

04 Following method we will apply to clear obstacles.

a. Wire.

(1) Crawl under if you can

(2) It may be possible for one man to, lie on the wire and flatten it down a bit, and for

the others to climb over his body.

(3) If you gave to cut wire, get someone to hold it on both sides of the cutler; if you do not do this, it will fly apart, make a noise, and possible hit you in the face.

b. Gates and Wooden Fences.

The best way is to crawl under them, the next best is to vault over them.

c. Walls.

Help one another up, and roll across the top, keeping flat, Be careful of your

snopaew, do not drop them over the wall.

d. Ditches, Hedges and Gaps.

Are likely to be covered by fire, cross them as fast as you can.

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SELCTING A ROUTE ACROSS COUNTRY

05. Before moving from one loc to another in battle, the soldier has to select a route which best

serves his purpose.

06. Selecting a route and maintaining direction.

The ideal route is one on which:- a. There are places to observe without being seen

b. There are good fire posns c. There is cover from En view

d. There is cover from En fire e. There are no obstacles to movement, ne; opes ground, marshy land, dense, woods etc.

07. When choosing a route, look carefully at the area and, subject to any orders received, decide on:

a. Where to make for b. The best way to get there, split into bounds

c. Where to run, walk or crawl. From this the time taken for the route can be estimated. d. Distant landmarks to help in maintaining direction

08 Move in bounds from one pnswae of alwaosbn to another, choosing each route as taught. After

each bound confirm direction from the distant landmarks.

09 To assist in maintaining direction the fool may also be used ;- a. Maps air photographs and compass

b. The pawwsasae of the sun

10 Types of Cover

a. Dead ground The ground which cannot be seen from ieitisnppemene. Thus it provides cover from

obsn and direct fire, but does not give protection from mortars and artillery fire.

b. Streambeds and Ditches

These provide cover from view. They are however obvious approaches and will normally

be covered by en fixed lines of fire, triflers etc.

c. Hedges and Bushes.

There provide cover from view, but no protection from direct fire. Isolated bushes and

trees are obvious places to take cover and should therefore be avoided.

d. Woods.

These provides cover from obsn from ground and air. The main danger is from en mortar

and arty fire.

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CHAPTER 12

INTER SECTION/ RE-SECTION

FINDING YOUR OWN POSITION (RESECTION)

01. To find and plot ones own position on the map the following steps are to be followed

a. Orientate the map

b. Observe the surrounding area and select an ‘object’ on the ground with can also be identified on the map.

c. With the used of a compass, measure the bearing to the selected object and record it.The

bearing recorded is the forward magnetic bearing.

d. Convert the forward magnetic bearing to its forward grid bearing and record it.

e. Convert the record forward grid bearing to its back bearing and record it.

f. Plot the recorded back bearing (grid) on the map (from the object shown on the map)

g. Select another object as per Para. 1, b about and carry out the process as per the steps given in Para ”I” sub Para “c, d, e” and “f” above.

02. The point at which the two lines cross/ meet is the own position of the observer (on the map)

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FINDING THE POSITION OF A DISTANT OBJECT (INTERSECTION)

03. To determine and plot the position of an object at which the position on the map is unknown but

is visible on ground the following step are to be followed.

a. Orientate the map

b. Select and take up a position on ground from which the object can be seen. (The position selected should be one that could be identified on the map).

c. With the use of a compass take a forward magnetic bearing to the object and record it.

d. Convert the forward magnetic bearing to its forward grid bearing.

e. Plot the recorded forward grid bearing (from the point of observation) on

the map. f. Select and take up another position on the ground and carry out the process as per the

step given in Para 1 sub Para “c”, “d” aed „‟i”

04. The point at which the two line cross / meet is the position of the object (on the map)

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CHAPTER 13

INTRODUCTION TO GLOBAL POSITIONING SYSTEM

(GPS)

The design of GPS is based partly on similar ground-based radio-navigation systems, such as

LORAN and the Decca Navigator developed in the early 1940s, and used during World War II. In 1956, Friedwardt Winterberg proposed a test of general relativity (for time slowing in a strong gravitational

field) using accurate atomic clocks placed in orbit inside artificial satellites. (To achieve accuracy requirements, GPS uses principles of general relativity to correct the satellites' atomic clocks. Additional

inspiration for GPS came when the Soviet Union launched the first man-made satellite, Sputnik in 1957. Two American physicists, William Guier and George Weiffenbach, at Johns Hopkins's Applied Physics

Laboratory (APL), decided on their own to monitor Sputnik's radio transmissions.Within hours they realized that, because of the Doppler effect, they could pinpoint where the satellite was along its orbit

from the Doppler shift. The Director of the APL gave them access to their UNIVAC to do the heavy calculations required. When they released the orbit of Sputnik to the media, the Russians were

dumbfounded to learn how powerful American computers had become, as they would not have been able to calculate the orbit themselves. The following spring, Frank McClure, the deputy director of the

APL, asked Guier and Weiffenbach to look at the inverse problem where you know the location of

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(ICBMs). Consid the satellite and you want to find your own location. (The Navy was developing the

submarine-launched Polaris missile, which required them to know the submarine's location.) This led them and APL to develop the Transit system. , based on phase comparison of signal transmission from

pairs of stations,[7]

became the first worldwide radio navigation system. Limitations of these systems drove the need for a more universal navigation solution with greater accuracy.

While there were wide needs for accurate navigation in military and civilian sectors, almost none of those were seen as justification for the billions of dollars it would cost in research, development,

deployment, and operation for a constellation of navigation satellites. During the Cold War arms race, the nuclear threat to the existence of the United States was the one need that did justify this cost in the

view of the United States Congress. This deterrent effect is why GPS was funded. It is also the reason for the ultra-secrecy at that time. The nuclear triad consisted of the United States Navy's submarine-

launched ballistic missiles (SLBMs) along with United States Air Force (USAF) strategic bombers and intercontinental ballistic missiles

The first satellite navigation system, Transit (satellite), used by the United States Navy, was first successfully tested in 1960. It used a constellation of five satellites and could provide a navigational fix

approximately once per hour. In 1967, the U.S. Navy developed the Timation satellite that proved the ability to place accurate clocks in space, a technology required by GPS. In the 1970s, the ground-based

Omega Navigation Systemered vital to the nuclear deterrence posture, accurate determination of the SLBM launch position was a force multiplier.

Precise navigation would enable United States submarines to get an accurate fix of their positions prior to launching their SLBMs. The USAF with two-thirds of the nuclear triad also had

requirements for a more accurate and reliable navigation system. The Navy and Air Force were developing their own technologies in parallel to solve what was essentially the same problem. To

increase the survivability of ICBMs, there was a proposal to use mobile launch platforms (such as Russian SS-24 and SS-25) and so the need to fix the launch position had similarity to the SLBM

situation.

In 1960, the Air Force proposed a radio-navigation system called MOSAIC (Mobile System for

Accurate ICBM Control) that was essentially a 3-D LORAN. A follow-on study called Project 57 was worked in 1963 and it was "in this study that the GPS concept was born." That same year the concept

was pursued as Project 621B, which had "many of the attributes that you now see in GPS and promised increased accuracy for Air Force bombers as well as ICBMs. Updates from the Navy Transit system

were too slow for the high speeds of Air Force operation. The Navy Research Laboratory continued advancements with their Timation (Time Navigation) satellites, first launched in 1967, and with the third

one in 1974 carrying the first atomic clock into orbi

With these parallel developments in the 1960s, it was realized that a superior system could be

developed by synthesizing the best technologies from 621B, Transit, Timation, and SECOR in a multi-service program.

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During Labor Day weekend in 1973, a meeting of about 12 military officers at the Pentagon

discussed the creation of a Defense Navigation Satellite System (DNSS). It was at this meeting that "the real synthesis that became GPS was created." Later that year, the DNSS program was named Navstar.

With the individual satellites being associated with the name Navstar (as with the predecessors Transit and Timation), a more fully encompassing name was used to identify the constellation of Navstar

satellites, Navstar-GPS, which was later shortened simply to GPS.

After Korean Air Lines Flight 007, carrying 269 people, was shot down in 1983 after straying

into the USSR's prohibited airspace, in the vicinity of Sakhalin and Moneron Islands, President Ronald Reagan issued a directive making GPS freely available for civilian use, once it was sufficiently

developed, as a common good. The first satellite was launched in 1989, and the 24th satellite was launched in 1994.

Initially, the highest quality signal was reserved for military use, and the signal available for civilian use was intentionally degraded (Selective Availability). This changed with President Bill Clinton

ordering Selective Availability to be turned off at midnight May 1, 2000, improving the precision of civilian GPS from 100 meters (330 ft) to 20 meters (66 ft). The executive order signed in 1996 to turn

off Selective Availability in 2000 was proposed by the US Secretary of Defense, William Perry, because of the widespread growth of differential GPS services to improve civilian accuracy and eliminate the US

military advantage. Moreover, the US military was actively developing technologies to deny GPS service to potential adversaries on a regional basis.

Over the last decade, the U.S. has implemented several improvements to the GPS service, including new signals for civil use and increased accuracy and integrity for all users, all while

maintaining compatibility with existing GPS equipment.

GPS modernization has now become an ongoing initiative to upgrade the Global Positioning

System with new capabilities to meet growing military, civil, and commercial needs. The program is being implemented through a series of satellite acquisitions, including GPS Block III and the Next

Generation Operational Control System (OCX). The U.S. Government continues to improve the GPS space and ground segments to increase performance and accuracy.

GPS is owned and operated by the United States Government as a national resource. Department of Defense (DoD) is the steward of GPS. Interagency GPS Executive Board (IGEB) oversaw GPS policy

matters from 1996 to 2004. After that the National Space-Based Positioning, Navigation and Timing Executive Committee was established by presidential directive in 2004 to advise and coordinate federal

departments and agencies on matters concerning the GPS and related systems. The executive committee is chaired jointly by the deputy secretaries of defense and transportation. Its membership includes

equivalent-level officials from the departments of state, commerce, and homeland security, the joint chiefs of staff, and NASA. Components of the executive office of the president participate as observers

to the executive committee, and the FCC chairman participates as a liaison.