Definition of Map Terms

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Definition of Map Terms

• Map Scale Chart Length / Earth Length
• Small Scale Big Area Less Detail
• 11,000,000
• Large Scale Small Area More Detail
• 1250,000
• Great-Circle Distance the shortest distance
  between two points on the curved surface of the
  earth lies along the great circle passing through
  these points
• Rhum Line is a line crossing all meridians at a
  constant angle.
• This is the line which an aircraft tends to
  follow when steered by a compass
• It is a greater distance than the great-circle
  route between the same two points

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Advantages to fly a Rhumb Line course instead of
great circle

1. In low latitude, a R/L closely approximates a
   great circle
2. Over short distances, a R/L and G.C. nearly
   coincide
3. A R/L between points on or near the same meridian
   of longitude approximates a great circle

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Definition of Map Terms

• Conformality (correct representation of angles)
  
• To be conformal, a chart must have uniform scale
  around any points, though not necessarily a
  uniform scale over the entire map.
• 2. Meridians and Parallels must intersect at
  right angle
• Mercator and Lambert are conformal

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Developed and Undeveloped Surface

• The surface of sphere or spheroid is said to be
  undevelopable because no part of it may be spread
  out flat without distortion
• A plane, cylinder or cone which can be easily
  flattened, is called developable surface .
• Projection on these surface are termed Conical,
  Cylindrical, and Azimuthal Projection

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Develop for flat of the earth
2.Cylinder
3.Cone
1.Plane
Cylindrical
Conical
Azimuthal
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Point of Tangency

• Names of Charts are different due to point of
  tangency such as a plane of projection tangent.
• Tangent at the Equator, called Equatorial Proj
• Tangent at the Poles, called Polar Proj
• Tangent at other places, called Oblique Proj

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Point of Tangency
N
N
N
E
W
E
W
E
W
S
S
S
Tangent at Pole called POLAR
Tangent at Equator called EQUITORAIL
Tangent at other point called OBLIQUE
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????????????????? Projection

• The method of representing all or part of the
  surface of a sphere or spheroid on a plane
  surface is called a map or chart project.

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Projection
Gnomonic Proj (Proj from the center of the sphere)
Stereo Proj (Proj from the opposite side of the
sphere)
Orthographic Proj (Proj from the infinity)
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Azimuthal Projection

1. Polar Tangency 3 names
2. Polar Azimuthal Gnomonic Proj
3. Polar Azimuthal Stergographic Proj
4. Polar Azimuthal Orthographic Proj
5. Oblique Tangency 3 names
6. Oblique Azimuthal Gnomonic Proj
7. Oblique Azimuthal Stergographic Proj
8. Oblique Azimuthal Orthographic Proj

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Azimuthal Projection

• 3. Equitorail Tangency 3 names
• Equitorail Azimuthal Gnomonic Proj
• Equitorail Azimuthal Stergographic Proj
• Equitorail Azimuthal Orthographic Proj

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Common Charts Used in Navigation

1. Map Reading
2. Plotting and Measuring Course Directions and
   Distance

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Ideal Chart

• Comformality (?????????????????)
• Parallels and meridians must intersect at 90
• Scale or scale expansion must be the same along
  the meridians as it is along the parallels
• Scale vary point to point but it is the same in
  all direction (Scale of any point independent
  from Azimuth)

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Ideal Chart

• 2. Constant and Correct Scale
• Constant ratio to bear to distance on the earth
• 3. Correct Shape Representation
• 4. Correct Area Representation
• 5. Coordinate Easy to Located
• 6. Rhumd Lines as Straight Lines (Mercator map)
• 7. True Azimuth

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Cylindrical Projection (Mercator)

• The only cylindrical projection used for air NAV
  is the MERCATOR
• GERHARD MERCATOR design this type of chart first
  in 1569
• The other types of the Mercator are Oblique
  Mercator and Transverse Mercator

N
S
Transverse Mercator Polar Cylindrical Gnomonic
Proj
Oblique Mercator
Plane Mercator
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Mercator Projection

• Its graticule can be imagined by visualizing a
  cylinder tangent at the equator to a translucent
  globe with a light source at the center.
• All parallels and meridians on the globe will be
  projected on the cylinder as straight lines
  crossing at right angles
• Meridians will be evenly spaced, whereas
  distance between parallels will increase rapidly
  with latitude.
• Scale on a Mercator is true only along the
  equator. Elsewhere it expands as the secant of
  the latitude, so that at 60N or S , scale is
  twice that at the equator.

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• Best suited for use Mercator Projection is within
  25 - 30 of the equator
• In low latitudes, rhumb line and great circle
  will be close together at middle and upper
  latitudes the amount of divergence becomes quite
  marked.
• The great-circle route will always be shorter,
  and it is part of the navigators duty to
  determine whether the bother of plotting and the
  increased risk of error in flying a series of
  changing heading is justified by the saving in
  distance.

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Characteristic of Mercator

• Conformality
• The meridians and parallel appear as straight
  lines, intersected together at right angle
• Area
• The area is not equal and are Greatly exaggerated
  in height Lat.
• Scale
• Scale correct only at the equator else where it
  expand as the secant of Lat .
• Using mid-lat scale to measure distance
• Great Circle appear as curve line convex to the
  nearest pole
• RHUM Line appear as a straight lines (The
  meridian parallel together)
• Rhum Line is the lines the success that cross the
  successive meridian at the same angle

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• Rhumb Line
• Between 2 points, the shortest distance is the
  great circle
• Fly by Rhum Line Track, the pilot must not change
  HDG all the time

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The Advantage of Mercator

1. Position in Lat and Long are easy to plot
2. Easy to fly follow R/L track

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The Disadvantage of Mercator

1. Difficulty of measuring large distance accurately
2. Conversion angle (C.A) must be applied to Great
   Circle bearing before plotting
3. The chart is useless in polar region above 80N
   or S since the polar cannot be shown conversion
   angle

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Conversion Angle

• The meridians converge towards the poles . A
  Great Circle (GC) gives shortest distance between
  2 positions while R/L running between the same
  position cut meridian at the same angle.
• It is spiral curve and therefore represent a
  longer distance that means that there will be a
  difference between the R/L angle which the GC
  angle at the start point and the ending point of
  the track

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Conversion Angle

• Conversion Angle (CA) is the angular difference
  between a great circle bearing and a R/L bearing
• Or angle between a great circle are joining two
  places on earth and a R/L between the two places
• CA (C(CH) Long /2) sin mean Lat

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• Difference of Long (D Long) is the angular
  difference between two longitude angle from 0
  Long to 180º E and 180º W Long such as from A
  to B DLong 150-15 135 W

Pri-meridian Greenwich Meridian
15ºW
DLong 135ºW
NP
150ºW
Anti-meridian
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• Change of Long (CH.Long) is the angular
  difference between two Longitude angles (In case
  of crossing prime-meridian or anti-meridian
• From A to C CH.Long 15W 60E 75E
• From C to B CH.Long 120E 30W 150W
• (180-60)(180-150)

CH.Long 75ºE
A 15ºW
C 60ºE
Note Same Direction (-) Difference
Direction ()
East
West
CH.Long 150ºW
B 150ºW
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• Difference of Lat (DLat) is the angular
  difference between two Lat. Angle . For instance,
  the north pole and the equator have a DLat of
  90º from the north pole to the equator the DLat
  is 90ºS. If from the south pole to equator ,
  DLat is 90º N
• From 20ºN to 40ºN DLat 20ºN
• 1º 60 NM yield 20ºN 2060 1200 NM

40ºN
20ºN
0º
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• Change of Lat (CH.Lat) is the angular different
  between two Lat angle (in case of crossing
  equator) such as from 30ºN to 30ºS CH.Lat is
  60ºS. if from 30ºS to 30ºN CH.Lat 60ºN

CH.Lat 60ºN
30ºN
0º
30ºS
CH.Lat 60ºS
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• Example, When the A/C is in position Lat3515S
  Long 1045E and ground station is Lat 2545S
  Long 0215W what is conversion angle value?
• Solve
• CAD(CH) Long /2 sin mean Lat
• CH Long 1045E 0215W
• 13
• Mean Lat (3515S 2545S) / 2
• 61/2 3030 31
• CA. (13 /2) sin 31
• 3

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Conic Projection

• The Conic Projection bases on cone tangent reduce
  earth every place
• The great majority of aeronautical chart in use
  today are based on conic projection
• There are 2 classes of conic proj.
• Simple Conic Proj with one Standard Parallel
  (S.P.) a lot of error
• Conic Proj with 2 S.P. And expand out of S.P.

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Lambert Conformal Conic Projection

• In a simple conic project the cone is held
  tangent to the globe along a line of latitude
  called the standard parallel.
• Scale is exact everywhere along this standard
  parallel, but increase rapidly above and below
• Lambert visualized the cone as making a secant
  cut, thus giving two standard parallels
• Scale along both is exact. Between them, scale is
  too small, beyond them too large.

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• For equal distribution of scale error, standard
  parallels are chosen at one-sixth and five-sixths
  of the total spread of latitude to be
  represented.
• To map the U.S, whose lat is from 25 to 49 ,
  standard parallels of 29 and 45 (one-sixth
  and five-sixths of the total spread ) would
  produce an equal distribution of scale error.

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Conic Projection
Simple Conic Proj with one Standard Parallel
(S.P.)
Lambert Conic Proj with two Standard Parallel
(S.P.)
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101
100
98
100
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The Lambert

• All meridians are straight lines that meet in a
  common point beyond limits of the map
• Parallels are concentric circles whose center is
  at the point of intersection of the meridians
• Meridians and parallels intersect at right angles
• Since scale is very nearly uniform around any
  point on a given chart, it is considered a
  conformal projection
• For map reading and radio navigation the
  projection is unequaled , and most areas of the
  world through 80 latitude are covered by
  aeronautical charts with scale of 1500,000 and
  11,000,000
• Above 80 , scale on a standard Lambert is too
  inaccurate for navigational use.

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Characteristic of The Lambert

• Conformal
• Scale correct on S.P. contracted inside and
  expand outside
• Area not an equal area
• Shape distortion small
• GC. curves concave to parallel of origin
  considered as straight line
• Rhumb Line curves concave to nearer pole
• Graticule meridians straight line ,
• - parallel concentric circle

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Polar Stereographic Projection

• A flat surface is used, touching the N.P.
• The light is at the S.P.
• The polar sterographic is modified by using a
  secant plane instead of tangent plane
• A secant ????????????????????????

NP
90N
SP
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• Modified polar stereographic proj. used secant
  plane as plane of tangency (Graticule)
• The meridians are straight lines, radiating from
  the pole.
• The parallels are concentric circles expands away
  from the pole

180
NP
090
270
0
Polar Sterographic Graticule
Greenwich Meridian
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Characteristic of Stereographic

1. Conformal
2. Correct at pole tangency
3. Shapes distorted away from pole
4. Area distorted away from pole
5. GC. Curve concave to pole to 90 N, considered as
   straight line about 70N
6. Polar Stereographic used only 80N near north and
   south pole

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Map Reading

• Determination of the aircraft position by
  matching natural or built-up features with their
  corresponding symbol on a chart
• Parallels and Meridians

Prime Meridian is 0 reference for Lat Pass
Greenwich
Parallel of Latitude
Equator is 0 reference for Lat
Longitude Meridian
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• Latitude and Longitude
• Latitude range from 0 at the equator to 90N and
  90S at the pole
• Longitude is measured around the earth both
  eastward and west ward from Prime meridian,
  through 180
• Geographic Coordinate System
• Read intersection of Latitude and Longitude
• Lat first then Long
• U-Tapao Lat 1240N Long 10104E

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• Grid System
• GEOREF System (GEO GRAPHIC REFENCE SYSTEM)
• Consist of 4 letters and 4 numbers
• Divided meridian 360 / 15 24 spaces
• Each 24 has letter run from A to Z except I and
  O, start from south pole 90S and Long 180
• Divided Latitude 180 / 15 12 spaces
• Each 12 space has letter run from A to M except I
  
• Total 288 spaces (15 15 º) per each
• 2. Each sqr (15 15 º) divided by 15º 1º
• Define letter A to Q except I and O
• Total 225 spaces (1 1 º) per each
• 3. Each 1º divided by 60 second
• Reading Right Up or Long - Lat

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M N P Q R S T U V W X Y Z A B C D E F G H J K L
L
K
J
H
G
F
E
D
C
B
A
M N P Q R S T U V W X Y Z A B C D E F G H J K L
UG
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Q
P
O
N
M
L
K
J
H
G
F
E
D
C
B
A B C D E F G H J K L M N P Q
UGEK3010
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Aeronautical Chart

• Charts for Visual Flight Rules (VFR)
• World Aeronautical Charts (WAC) 11,000,000
• Sectional Charts 1500,000
• VFR Terminal Area Charts 1250,000
• Charts for Instrument Flight Rules (VFR)
• Enroute Chart
• Standard Instrument Departure (SID)
• Standard Terminal Arrival (STAR)

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World Aeronautical Chart (WAC)

• WACs are used for plotting and pilotage
• WAC is published by the US.Coast and Geodetic
  Survey
• Scale is 11,000,000 They are based on
• Lambert conformal project 0 to 80N and 80S
• Modified Polar Stereographic Project from 80N
  and 80S to the pole

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?????????????????

1. ??????????????????????? (Topographical Symbols)
2. ????????????????????????? (Aeronautical Symbols)

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??????????????????????? (Topographical Symbols)

• ??????????????????????????? ?? ? ????
• ????????????? (Contour Lines)
• ??????????????????????????????????????????????????
  ???
• ????????????????????????? ???????????????????????
• ?????????????????????????? ???????????????????????
  ???????
• ?????? (Gradients Tints)
• S.L. 1,000 ft dark green
• 1,000 2,000 ft weak green
• 2,000 10,000 ft brown to dark brown

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• 3. ?????????? (Spot Elevation)
• ?????????????????????????????? ???????????????
• 4. ??????????????????? (Hachure or Shading)
• ?????? ??????????????? ??????? ?????????
• 5. ???????????????????? (Drainage or
  Hydrography)
• Blue
• 6. ?????????????????????????????????? (Cultural
  Features)
• Chart Legend
• 7. ????????????????????? (Vegetation)