map reading - direction
DESCRIPTION
Direction refers to the relative (相對的) position (位置) between two points measures with a compass (羅盤/指南針) and expressed in terms of compass readings. There are 3 ways to measure the direction.TRANSCRIPT
Map Reading - Direction
Direction
• refers to the relative ( 相對的 ) position ( 位置 ) between two points measures with a compass ( 羅盤 / 指南針 ) and expressed in terms of compass readings.
• There are 3 ways to measure the direction.
Which are these three ways?
• (1) Compass Points• (2) Whole Circle Bearing• (3) Reduced Bearing
How many directions do you know?
Direction names in English東北 , 東南 , 西北 , 西南
Can you write the directions on the blackboard?
Compass Point ( 羅盤方位 )
N
E
S
W
NNENE
ENE
ESESE
SSESSWSW
WSW
WNW
NWNNW
•North, south, east and west are the four cardinal ( 主要 / 基本的 ) points. •Subdivide into 12 more points. •There are a total of 16 points as shown below.
東
南
西
北
Compass Point (羅盤方位 )
N
E
S
W
NNENE
ENE
ESESE
SSESSWSW
WSW
WNW
NWNNW
0º
90 º
180 º
270 º
45º
135º225º
315º
•All points are shown in directional points only. •All points are divided equally, so we can know its degrees.
22.5o
Teacher Desk
Terry Simon Apple KenChing Pinky Steve
Chris Ann TonyWong Ron Katrina Yuki Terence
Sally Tim Victoria Jacky Herman King Ceci
ThomasWongHingYing
Tse KaFai Sharon Janice
Lo Fish KenWong
StevenWong
Ming JennieLeung Yu
ChengKaHei
Horal StephenLam
Jammi Gary TonyYiu Priscilla Janice
ChanKelvinWong
12 13 14 15 16 17 18 19 20 21 22
71 70 69 68 67 66 65 64
“Compass Points” Game
W
N
NE
E
SSESW
NW
Where is the treasure?• Start from 1266.• Go to the north 1 step.• Go to the east 2 steps.• Go to the south 1 step.• Go to the SE 1 step.• Go to the NE 2 steps.• Go to the NW 2 steps.• Go to the East 3 steps.• Go to the SE 2 steps.• Go to the NE1 step.
Teacher Desk
Terry Simon Apple KenChing Pinky Steve
Chris Ann TonyWong Ron Katrina Yuki Terence
Sally Tim Victoria Jacky Herman King Ceci
ThomasWongHingYing
Tse KaFai Sharon Janice
Lo Fish KenWong
StevenWong
Ming JennieLeung Yu
ChengKaHei
Horal StephenLam
Jammi Gary TonyYiu Priscilla Janice
ChanKelvinWong
12 13 14 15 16 17 18 19 20 21 22
71 70 69 68 67 66 65 64
“Compass Points” Game
1. Start from 1266.2. To the north 1 step.3. To the east 2 steps.4. To the south 1 step.5. To the SE 1 step.6. To the NE 2 steps.7. To the NW 2 steps.8. To the East 3 steps.9. To the SE 2 steps.10. To the NE 1 step.
Where is the treasure?
N
E
S
W
Whole Circle Bearing (方位角 )•More accurately, we can use whole circle bearing.•The compass is divided into 360o counting clockwise from the north.
360 ºHere is one more example.
N
E
S
225º
順時針方向
Reduced Bearing (象限角 )
N
E
S
W
•It is shown by both the directional points (N,E,S and W) and degree. •The compass is divided into 4 parts. The direction is read either from the North or the South, but not at the East and West. Therefore, compass bearing can never be greater than 90 º.
S45ºE
How to determine whether we should use “N” or “S”? It depends on the point we measure is closer to N or S. In the figure on the left, the point we measure is closer to the South, so we start from the South and have the reduced bearing “S45 º E”.
Let’s have some more examples...N
E
S
W
N
E
S
W
N
E
S
W
N45ºE
S45 ºW
N45 ºW Remember, Reduced Bearing never starts with “E” or “W” !
Let’s do a simple exercise first.
A
B
The direction of Point A from Point B is...N
A. Northwest
B. Southeast
C. West
D. SouthThe Reduced Bearing of Point X from Point Y is...
A. N45º E
B. S45º N
C. S45º W
D. W45º S X
YN
N
Compasspoint
Wholecirclebearing
Reducedbearing
NE
NW
045o N45oE
315o N45oW
Conversion from one to another measuring direction method
YOU ARE VERY SMART!
Sorry, please try again!
Conclusion
• Which three methods have we learned today?
E.g. SW, NW, NNE - Compass points
E.g. S71oE, N45oW
- Whole circle bearingE.g. 360o, 090o
- Reduced bearing
Let’s do exercise!