Mapwork skills.pptx
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Map skills for grade 8 to 12
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Mapwork skills.pptx
- 1. Mapwork
- 2. Otavi
- 3. Characteristic of a map ā¢ Scale ā¢ Title ā¢ Legend/ Key/ Reference ā¢ Direction
- 4. Types of Scale Word Scale : 2 cm on the map represents 1 km on the ground or in reality Ratio Scale : 1: 50 000 Fraction scale: 1 50 0000 Linear Scale:
- 5. Determining size of the scale ā¢ When determining size of ratio scale, you look at how big is the number after the colon (:). If the number is bigger than its shows a small scale but if the number is smaller then it indicates big scale. ā¢ The number show how much detail and information is indicated by the map. The bigger the number the more information covered but less detail, while smaller number means less information but detailed ā¢ Example, 1 : 50 000 is a small scale while 1 : 25 000 is a large scale
- 6. Measuring and calculating distance on the map 1. Measure distance on map in cm. 2. When measuring a curve line you use a strip of paper and when measuring a straight line use a ruler. 3. Apply formula Distance on map unit asked (m or km) Ć Scale 4. Unit asked in m divide by 100 and in Km divide by 100 0000
- 7. Example How to calculate distance For instance, the distance measured on the map between two points is 5cm and the map scale 1: 50 000 ā¢ To kilometer (Km) 5cm 100 000 Ć 50 000 = 2.5 Km 1 2 x 5cm= 2.5 Km ā¢ To meter (m) 5cm 100 Ć 50 000 = 2500 m
- 8. Converting scales to Another (a) Ratio to fraction (Ratio scale, 1 : 50 000) Expressed as a Normal fractional scale. 1 50 000 Express scale as half a fractional scale. 1 50 000 š„ 1 2 = 1 100 000 Express scale as a double fractional scale. 1 50 000 š„ 2 = 1 25 000
- 9. (b) Ratio to word scale (Ratio Scale,1:50 000) 1:50 000 1cm=50 000 cm 1cm= 50 000 100 000 1cm = 0.5km 1cm on the map represent 0.5km on the ground or 1cm on the map represents 50 000 cm on the ground. 2cm on the map represents 1km on the ground.
- 10. (c) From word scale to ratio scale. word scale: 2cm on the map represent 1km on the ground 2cm=1km 2cm= 1km x 100 000 2cm=100 000cm 2šš 2 = 100 000cm 2 1cm=50 000cm 1:50 000
- 11. (d) From linear to word scale to ratio scale First measure the segment of the scale in cm, e.g. you get 2cm. To Word scale 2cm= 1000 m 2cm on the map represents 1000m on the ground 2cm
- 12. To Ratio scale 2cm= 1000 m 2cm= 1000 x 100 2cm/2=100 000/2 1cm=50 000 cm 1: 50 000
- 13. Determining Height ā¢ Height on the map is represented in metres (m) Height on a topographic map is presented by: ļ¼Spot Height e.g. 1170 ļ¼Trigonometrical Beacon e.g. 330 1274 ļ¼ Contour lines
- 14. Calculating gradient ā¢ Gradient refers to how steep is the slope ā¢ A gradient of 1: 5 is steeper than the gradient of 1:50. ā¢ Reason: A gradient of 1:5 has to cover less distance on the actual ground for 1 unit increase in height While a gradient of 1:50 has to cover more distance on the actual ground for 1 unit increase in height.
- 15. How is gradient calculated ā¢ Gradient= Vertical interval (VI) Horizontal interval (HI) ā¢ VI= Highest height ā Lowest Height ā¢ HI = Distance on the map 100 x Scale of the map
- 16. Example Calculate the gradient between spot height 1174 and spot height 1274, on a topographic map if the distance between them is 4cm. The map scale is 1: 50 000. VI = highest ā lowest VI=1274m - 1174m VI= 100m
- 17. ā¢ HI= Distance on the map 100 x Scale ā¢ HI= 4šš 100 x 50 000 ā¢ HI= 2000 m
- 18. ā¢ Gradient= Vertical interval (VI) Horizontal interval (HI) ā¢ Gradient= 100 Ć· 2000 Ć· 100 100 ā¢ Gradient = 1 20 ā¢ Gradient= 1:20 (Change fractional scale into ratio scale)
- 19. Direction ā¢ Make use of sixteen compass directions. Direction Web Cross
- 20. How to get direction ā¢ Step 1: Connect the two features involved with a light pencil ā¢ Step 2: Draw a true north line on the starting feature ā¢ Step 3 : Draw a neat cross, on the starting point ā¢ Step 4 : find the direction using the neat cross
- 21. Example Find the direction of B from A. ā¢ Mark the North line on starting point at A ā¢ Draw a direction neat cross, on the starting point (at A) A B x x ā¢ Draw the line connecting A to B. N NE E SE S NW SW ā¢Direction of B from A is South East (SE)
- 22. Bearings Rules: ā¢ Are always written in three figures (e.g. 040Ā° instead of 40Ā°) ā¢ Always measure the angle clockwise from the True North
- 24. Measuring bearingsā¦ Find the bearing of B from A. ā¢ Mark the North line on at A (if there isnāt a North line draw one in) ā¢ Place your protractor over the north line with 0Ā° at the top (true north). A B x x ā¢ Draw the line connecting A to B.
- 25. Measuring bearingsā¦ Find the bearing of B from A. ā¢Measure the angle clockwise from the North line to B ā¢ Give the answer as a three- figure bearing The bearing of B from A is 134Ā°. A B
- 26. Measuring bearingsā¦ Find the bearing of A from B. ā¢ Mark the North line on at B (if there isnāt a North line draw one in) ā¢ Measure the angle clockwise from the North line to A A B x x ā¢ Draw the line connecting B to A.
- 27. Measuring bearingsā¦ Find the bearing of A from B. ā¢ Place your protractor over the north line with 0Ā° at the bottom. ā¢ The angle has gone past 180Ā° so you will need to add your measurement to 180Ā° A B x x ā¢ Because you are measuring clockwise you need to measure the exterior angle.
- 28. Measuring bearingsā¦ Find the bearing of A from B. ā¢ The measurement from the bottom 0Ā° is 135Ā°. The bearing of A from B is 313Ā°. A B x x ā¢ 133Ā° + 180Ā° = 313Ā°. 135 Ā°
- 29. Determining location ā¢ Involves using Latitude and longitude ā¢ Latitude are line that runs from the west to the east while Longitude lines that runs from north to the south Symbols used ā¢ Degrees(Ā°), minutes (ā) and seconds (ā). How to write Location( coordinates) ā¢ In Southern Hemisphere we first write the latitude degree, minutes, seconds reading follow by south direction. ā¢ Then followed by the longitude degree, minutes, second reading followed by the east direction. ā¢ 24Ā°51ā45āāS29Ā°15ā30āāE
- 31. Examples how to determine location? Find location of A (see next slide) a) In Degree and Minutes ā¢ Latitude reading will be 17Ė23 ĢS ā¢ Longitude reading will be 19Ė38 ĢE ā¢ Therefore the Location will be 17Ė23 ĢS 19Ė38 ĢE
- 32. b) Degrees, Minutes and Second For you to do this you need a ruler and calculator. See examples below
- 33. A ā¢ Firstly connect latitudes and longitudes lines to make a grid ā¢ For latitude seconds measure from first latitude to the second latitude line in mm (b). ā¢ Measure from first latitude to the point in mm (a). ā¢ Use formalar š š x 60ā ā¢ The final answer you add it to degrees and minutes of latitude
- 34. A ā¢ Firstly connect latitudes and longitudes lines to make a grid ā¢ For longitude seconds measure from first longitude to the second longitude line in mm (b). ā¢ Measure from first longitude to the point in mm (a). ā¢ Use formalar š š x 60ā ā¢ The final answer you get add it to degrees and minutes of longitude
- 35. How to read other features on the map Relief ā¢ Look for region uplands and lowlands ā¢ State the highest point and the lowest point, ā¢ Recognize landform features such as Plateau, Valley. ā¢ Look for identifiable slopes ā convex, concave, steeper or Gentle.
- 36. Type of slopes on the map Gentle : Steep
- 38. Convex : Concave
- 39. Terraced Slope
- 40. Flat Topped hill
- 42. Spur
- 43. Valley
- 44. Saddle
- 45. Drainage ā¢ Describe drainage density of river (High, Low or Medium) depending on number of streams forming a drainage ā¢ Identify the drainage patterns (trellis, dendritic, radial, etc.) ā¢ Recognize if the rivers are perennial or not ā¢ Recognizable features of the river (waterfalls, rapids, braiding, meander, islands, ox bow lakes, etc) ā¢ Identify stage of river courses (upper, middle or lower)
- 46. Drainage Patterns Dendritric Pattern Deranged Pattern
- 47. Parallel Pattern Rectangular Pattern Trellis Pattern
- 48. Radial Pattern
- 49. Drainage Density
- 50. Land use A useful method is to consider economic activities: Primary economic activities a) Farming ā¢ Type of farming: Arable Farming (Crop Farming) or Pastoral Farming (livestock Farming) ā¢ For Arable farming look out for cultivation, irrigation furrows, canals and pipelines, farm dams and Silos. ā¢ For Livestock look out for kraals, windmills and dipping tanks
- 51. b) Mining ā¢ Open cast mining ā¢ Look for name of the mine, Opencast mine, service railways, mine dump, excavations and diggings. c) Forestry ā¢ Look out for plantations and forests names d) Fishing ā¢ Look out for coastal quays and harbours
- 52. Secondary economic activity industry (look for industrial location factors, market, raw material, power and water, labour, flat land and transport). Tertiary economic activity Look for services facilities indicated next to each service ā¢ Education (School, University and Colleges) ā¢ Recreation ( Caravan Park, Rec, Golf Course) ā¢ Health /Medical service (Clinic and Hospitals) ā¢ Shopping( Shops, Supermarkets and Store)
- 53. Transport and communication ā¢ Railways ā¢ Main Roads ā¢ Secondary roads ā¢ Landing Strips/ Airports ā¢ Hiking and Trail
- 55. Photographs ā¢ Horizontal photographs ā¢ High oblique ā¢ Low oblique ā¢ Vertical /aerial photographs
- 56. Horizontal photographs ā¢ Advantages ā¢ The photograph shows a lot of detail ā¢ Disadvantages ā¢ Shows a small area ā¢ Objects in the foreground block out objects in the background ā¢ Objects in the foreground appear larger than objects in the background ā¢ Cannot use them for map drawing
- 57. GROUND-LEVEL PHOTOGRAPH ļTaken at ground-level, as you would normally see things.
- 58. High oblique photographs ā¢ Taken from a high vantage point such as top of a building. ā¢ The horizon is visible Advantages ā¢ Covers a larger area ā¢ Shows a lot of information Disadvantages ā¢ Less detail in the foreground ā¢ Objects in the foreground block out objects in the background
- 59. HIGH OBLIQUE PHOTOGRAPH ļTaken from a high point (building), horizon is visible.
- 60. Low oblique photographs ā¢ These photographs are taken from a airplane at a angle. ā¢ Horizon is not visible ā¢ Advantages ā¢ They show a larger area ā¢ Shows much more information ā¢ Disadvantages ā¢ Objects in the foreground block out objects in the background ā¢ Objects in the foreground appear larger than objects in the background
- 61. LOW OBLIQUE PHOTOGRAPH ļTaken from an aero plane, horizon not visible.
- 62. Vertical photographs ā¢ Taken from a airplane but the camera is tilted vertically down. ā¢ Advantage ā¢ No hidden areas ā¢ Shows a lot of information ā¢ Used to draw maps ā¢ Disadvantages ā¢ Height and surface slopes are not easy to identify ā¢ A lot of experience is needed to obtain information from these photographs
- 63. Other Graphical analysis Know how to read and complete the graphs below ā¢ Bar graphs ā¢ Line graphs ā¢ Pie Chart ā¢ Divided Bar graph ā¢ Triangular graph ā¢ Wind rose