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Locating Places on Map

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Locating Places on Map Powered By Docstoc
					Locating Places on a
        Map
                 Cardinal Points
   The four main directions of
    a compass are known as
    cardinal points. They are
    north (N), east (E), south
    (S) and west (W).




                                   2
    Intercardinal (Ordinal) Points
   Sometimes, the
    intercardinal
    (ordinal) points of:
    •   north-east (NE),
    •   north-west (NW),
    •   south-east (SE) and
    •   south-west (SW)
    are shown on the
    compass.


                                     3
            Compass Bearings
   This compass shows
    degree
    measurements from
    0° to 360° in 10°
    intervals with:
    • north representing 0°
      or 360°
    • east representing 90°
    • south representing
      180°
    • west representing
      270°

                               4
                       Bearing
   The true bearing to a
    point is the angle
    measured in degrees in a
    clockwise direction from
    the north line. We will
    refer to the true bearing
    simply as the bearing.




                                 5
               Bearing Example
   For example, the
    bearing of point P is
    065º which is the
    number of degrees in
    the angle measured in
    a clockwise direction
    from the north line to
    the line joining the
    centre of the compass
    at O with the point P
    (i.e. OP).


                                 6
                        Compass Points

                           360/000o
                              N
Half way between                              Half way between
North and West     NW                          North and East
                                         NE




     270o   W                                 E   090o




                   SW                    SE
     Half way between                         Half way between
                              S
     South and West                            South and East
                             180o
                                                             7
                                    .
                                  Bearings
                                                360/000o
                                                     N
1. Measured from North.
                                                            060o
2. In a clockwise direction.                         60o
                                   270o     W               E       090o
3. Written as 3 figures.

                                                     S

                                                    180o
        N                            N                       N
                                                     315o



W        145o          E   W                    E     W                        E
                                     230o                   315o



                           230o
                145o                                                       8
        S                            S                          S
                                                Use your protractor to
     A 360o                   Bearings          measure the bearing of
  protractor is                                 each point from the
used to measure               360/000o          centre of the circle.
    bearings.                                   (Worksheet 1)
                        350o     N       020o
           315o                                       045o
                  NW
                                                NE


           290o
                                                     080o
    270o    W                                          E     090o


           250o                                      110o

                  SW                            SE
            225o       210o                          135o
                                 S       160o
                                180o
                                                                    9
                                     N
                                  360/000o
                                              030o
                          330o
                                                                    Estimate the
                   315o                               045o
                                                                     bearing of
                                                                    each aircraft
           290o                                                       from the
                                                                    centre of the
                                                            075o
                                                                    radar screen.

W 270o                                                             090o E

                                                        110o       Air Traffic
Control     250o
                                                                   Controller
Tower
                                                     135o
                   225o
                                       170o
                           200o
                                    180o                                     10
2-Jun-11
                                     S
                                           N
                                        360/000o
                                                    010o
                           325o               7
                                                                    040o            Estimate the
                                    8
                    310o                                     1                       bearing of
   ACE
                                                                           060o     each aircraft
Controller
                            11
                                                                                      from the
 contest
                       4
                                                    12                              centre of the
             280o
                                                                            2
                                                                                    radar screen.

W 270o                                                                             090o E
                      3
                                                                        5
               250o                     10                                         Air Traffic
 Control                                                 9                         Controller
                                                                            120o
 Tower
                235o
                                    6


                                 195o                            155o
                                             180o    Worksheet 2                             11
2-Jun-11
                                              S
                             Bearings

     Measuring the bearing of one point from another.

                                    To Find the bearing of Q from P.
                              N




                         P



                                                        118o
1. Draw a straight line between both points.
                                                       Q
2. Draw a North line at P.

3. Measure angle between.                                          12
                             Bearings

     Measuring the bearing of one point from another.

To Find the bearing of P from Q.


                                               N
                         298o
                         P




1. Draw a straight line between both points.
                                                   Q
2. Draw a North line at Q.

3. Measure angle between.                               13
                       Bearings: Fixing Position
 Trainee pilots have to to learn to be cope when the unexpected
 happens. If their navigation equipment fails they can quickly find
 their position by calling controllers at two different airfields for
 a bearing. The two bearings will tell the pilot where he is. The
 initial call on the controllers radio frequency will trigger a line on
 the radar screen showing the bearing of the calling aircraft.

  Airfield (A)
283.2 MHZ UHF


170o
                                          255o

                                                   Airfield (B)
                                                 306.7 MHZ UHF
            Thankyou


                                                                          14
           Bearings

           000/360o
              N




270o   W              E   090o




              S

             180o
                                 15
                   Grid Systems
   The most common way to locate a place on a
    map is to use a grid system.

   A grid system allows the location of a point on a
    map (or on the surface of the earth) to be
    described in a way that is meaningful and
    universally understood.




                                                        16
             Simple Grid System
   A simple grid is shown with the location of a point of
    interest that we want to describe

   In order for a point designation on a grid to be
    meaningful, there must be an origin to the grid which can
    be used to reference the point to.




                                                             17
             Alphanumeric Grid
   An alphanumeric grid
    uses letters and numerals
    to identify squares on a
    grid pattern.




                                 18
         Map Grid (Military Grid)

    A method to locate points on a map


    With this method, a system of numbered lines is
    superimposed on a map and position is stated by
    quoting the numbers of the lines that intersect at
    the point in question.




                                                         19
       Using the Military Grid

    For instance, let's
    utilize the military grid
    to determine which
    grid square the church
    is located in.




                                 20
        Identifying Grid Squares -
                  Easting

    First, go to the Western
    edge of the grid square that
    the object is in first. Then
    from that western edge, go
    up or down until you come
    to a number. In this case,
    going up or down yields the
    number 91. These are the
    first two digits for the square
    that the church is in.




                                      21
       Identifying Grid Squares -
                 Northing

    Secondly, go to the
    Southern edge of the grid
    square that the object is in.
    From that southern edge,
    go across until you come to
    a number. In this case, the
    number is 94. This
    represents the third and
    fourth digits for the square
    that the church is in.


    Hence, the church is in
    grid square 9194
                                    22
    Six Digit Military Grid Method

    With this method, you start out
    exactly the same way as the four
    digit method. Then ask yourself,
    how far over from that western edge
    is the church? To determine this,
    picture the grid square as if it was
    divided into ten equal vertical
    sections.


    The church is 6 sections over from
    the Western edge of the grid square.
    Therefore, the first three digits are
    916.


                                            23
           Fourth and Fifth Digits

    Now, to obtain the fifth and
    sixth digits, do the same as
    you did for the four digit
    method and ask yourself,
    how far up from the
    southern edge is the
    church? To determine this,
    picture the grid square as if
    it was divided into ten equal
    horizontal sections.


                                     24
         Six-digit Grid Reference

    The church is 5 sections up
    from the Southern edge.
    Therefore, the last three
    digits are 945.


    In summary, the church is
    located at 916945.




                                    25
                Questions

   Page 30, #1-10

   Page 33, Hamilton-Burlington Topographic
    Map Study, #1, 2.




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