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Map Reading

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

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Map Reading

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  1. Map Reading - Direction

  2. 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.

  3. Which are these three ways? • (1) Compass Points • (2) Whole Circle Bearing • (3) Reduced Bearing

  4. How many directions do you know?

  5. Video Show http://www.plk83.edu.hk/ckf/

  6. Direction names in English Can you write the directions on the blackboard? 東北, 東南,西北, 西南

  7. Compass Point (羅盤方位) • 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. 北 N NNW NNE NE NW ENE WNW 西 東 W E WSW ESE SW SE SSW SSE S 南

  8. Compass Point (羅盤方位) • All points are shown in directional points only. • All points are divided equally, so we can know its degrees. 22.5o 0º 315º N 45º NNW NNE NE NW ENE WNW 270 º 90 º W E WSW ESE SW SE SSW SSE S 135º 225º 180 º

  9. “Compass Points” Game N 71 70 69 68 67 66 65 64 NW NE E SE SW S 12 13 14 15 16 17 18 19 20 21 22 W

  10. 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.

  11. “Compass Points” Game 71 70 69 68 67 66 65 64 12 13 14 15 16 17 18 19 20 21 22 Where is the treasure? 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.

  12. Whole Circle Bearing (方位角) • More accurately, we can use whole circle bearing. • The compass is divided into 360o countingclockwisefrom the north. 順時針方向 N 360 º Here is one more example. N W E E S 225º S

  13. Reduced Bearing (象限角) • 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. 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”. N W E S45ºE S

  14. Let’s have some more examples... N N N45ºE W E W E S45 ºW S S N Remember, Reduced Bearing never starts with“E”or“W” ! N45 ºW W E S

  15. Let’s do a simple exercise first.

  16. N The direction of Point A from Point B is... A. Northwest B. Southeast C. West D. South A B The Reduced Bearing of Point X from Point Y is... A. N45º E B. S45º N C. S45º W D. W45º S N Y N X

  17. Conversion from one to another measuring direction method N45oE 045o N45oW 315o

  18. YOU ARE VERY SMART!

  19. Sorry, please try again!

  20. Conclusion • Which three methods have we learned today? - Compass points E.g. SW, NW, NNE - Whole circle bearing E.g. 360o, 090o - Reduced bearing E.g. S71oE, N45oW

  21. Let’s do exercise!

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