Mapwork skills.pptx

Map skills for grade 8 to 12

1. Mapwork

2. Otavi

3. Characteristic of a map Scale Title Legend/ Key/ Reference 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: Linear Scale:  

5. Determining size of the scale 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. 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 Example, 1 : 50 000 is a small scale while 1 : 25 000 is a large scale

6. Measuring and calculating distance on the map Measure distance on map in cm. W hen measuring a curve line you use a strip of paper and when measuring a straight line use a ruler. 3. Apply formula × 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 d istance measured on the map between two points is 5cm and the map s cale 1: 50 000 To kilometer (Km) × 50 000 = 2.5 K m x 5cm= 2.5 Km To meter (m) × 50 000 = 2500 m  

8. Converting scales to Another Ratio to fraction ( R atio scale, 1 : 50 000) Expressed as a Normal fractional scale. Express scale as half a fractional scale. = Express scale as a double fractional scale. =  

9. (b) Ratio to word scale ( Ratio Scale,1:50 000 ) 1:50 000 1cm=50 000 cm 1cm= 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 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 Height on the map is represented in metres (m) Height on a topographic map is presented by: Spot Height e.g. 1170 Trigonometrical Beacon e.g. 330 1274 Contour lines

14. Calculating gradient Gradient refers to how steep is the slope A gradient of 1: 5 is steeper than the gradient of 1:50. 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 Gradient= VI= Highest height – L owest Height H I 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 – lowest VI=1274m - 1174m VI= 100m

17. HI= x Scale HI= x 50 000 HI= 2000 m  

18. Gradient= Gradient= Gradient = Gradient= 1:20 ( Change fractional scale into ratio scale)  

19. Direction Make use of sixteen compass directions. Direction Web Cross

20. How to get direction Step 1: Connect the two features involved with a light pencil Step 2: Draw a true north line on the starting feature Step 3 : Draw a neat cross , on the starting point Step 4 : find the direction using the neat cross

21. E xample Find the direction of B from A. Mark the North line on startin g point at A Draw a direction neat cross , on the starting point (at A) A B x x Draw the line connecting A to B. N NE E SE S NW SW Direction of B from A is South East (SE)

22. Bearings Rules: Are always written in three figures (e.g. 040° instead of 40°) Always measure the angle clockwise from the True North

23. Matching compass points… 360° 000° 023° 045° 068° 090° 113° 225° 158° 180° 338° 315° 293° 270° 248° 135° 203°

24. Measuring bearings… Find the bearing of B from A. Mark the North line on at A (if there isn’t a North line draw one in) Place your protractor over the north line with 0° at the top (true north). A B x x Draw the line connecting A to B.

25. Measuring bearings… Find the bearing of B from A. Measure the angle clockwise from the North line to B Give the answer as a three-figure bearing The bearing of B from A is 134°. A B

26. Measuring bearings… Find the bearing of A from B. Mark the North line on at B (if there isn’t a North line draw one in) Measure the angle clockwise from the North line to A A B x x Draw the line connecting B to A.

27. Measuring bearings… Find the bearing of A from B. Place your protractor over the north line with 0° at the bottom. The angle has gone past 180° so you will need to add your measurement to 180° A B x x Because you are measuring clockwise you need to measure the exterior angle.

28. Measuring bearings… Find the bearing of A from B. The measurement from the bottom 0° is 135°. The bearing of A from B is 313°. A B x x 133° + 180° = 313°. 135 °

29. Determining location Involves using Latitude and longitude Latitude are line that runs from the west to the east while Longitude lines that runs from north to the south Symbols used D egrees(°), minutes (‘) and seconds (“). How to write Location( coordinates) In Southern Hemisphere we first write the latitude degree, minutes, seconds reading follow by south direction. Then followed by the longitude degree, minutes, second reading followed by the east direction. 24°51’45’’S29°15’30’’E

30. Examples how to determine location? Find location of A ( see next slide ) In Degree and Minutes Latitude reading will be 17˚23 ̒S Longitude reading will be 19˚38 ̒E Therefore the Location will be 17 ˚23 ̒ S 19 ˚38 ̒E

31. b) Degrees, M inutes and Second For you to do this you need a ruler and calculator. See examples below

32. A Firstly connect latitudes and longitudes lines to make a grid For latitude seconds measure from first latitude to the second latitude line in mm (b). Measure from first latitude to the point in mm (a). Use formalar x 60” The final answer you add it to degrees and minutes of latitude  

33. A Firstly connect latitudes and longitudes lines to make a grid For longitude seconds measure from first longitude to the second longitude line in mm (b). Measure from first longitude to the point in mm (a). Use formalar x 60” The final answer you get add it to degrees and minutes of longitude  

34. How to read other features on the map Relief Look for region uplands and lowlands State the highest point and the lowest point , Recognize landform features such as Plateau , Valley. Look for identifiable slopes – convex, concave, steeper or Gentle.

35. Type of slopes on the map Gentle : Steep

36. Terraced : Vertical

37. Convex : Concave

38. Terraced Slope

39. Flat Topped hill

40. Conical hill/Pointed butte

41. Spur

42. Valley

43. Saddle

44. Drainage Describe drainage density of river (High, Low or Medium) depending on number of streams forming a drainage Identify the drainage patterns (trellis, dendritic, radial, etc.) Recognize if the rivers are perennial or not Recognizable features of the river (waterfalls, rapids, braiding, meander, islands, ox bow lakes, etc ) Identify stage of river courses (upper, middle or lower)

45. Drainage Patterns Dendritric Pattern Deranged Pattern

46. Parallel Pattern Rectangular Pattern Trellis Pattern

47. Radial Pattern

48. Drainage Density

49. Land use A useful method is to consider economic activities: Primary economic activities a) Farming T ype of farming: Arable Farming ( C rop Farming) or Pastoral Farming (livestock Farming) For Arable farming look out for cultivation, irrigation furrows, canals and pipelines, farm dams and Silos. For Livestock look out for kraals, windmills and dipping tanks

50. b) Mining Open cast mining Look for name of the mine, Opencast mine, service railways, mine dump, excavations and diggings. c) Forestry Look out for plantations and forests names d) Fishing Look out for coastal quays and harbours

51. 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 Education (School , University and Colleges ) Recreation ( Caravan Park, Rec, Golf Course) Health /Medical service (Clinic and Hospitals) Shopping ( Shops, Supermarkets and Store)

52. Transport and communication Railways Main Roads Secondary roads Landing Strips/ Airports Hiking and Trail

53. Road Patterns/Street Patterns

54. Photographs Horizontal photographs High oblique Low oblique Vertical /aerial photographs

55. Horizontal photographs Advantages The photograph shows a lot of detail Disadvantages Shows a small area Objects in the foreground block out objects in the background Objects in the foreground appear larger than objects in the background Cannot use them for map drawing

56. GROUND-LEVEL PHOTOGRAPH Taken at ground-level, as you would normally see things.

57. High oblique photographs Taken from a high vantage point such as top of a building. The horizon is visible Advantages Covers a larger area Shows a lot of information Disadvantages Less detail in the foreground Objects in the foreground block out objects in the background

58. HIGH OBLIQUE PHOTOGRAPH Taken from a high point (building), horizon is visible.

59. Low oblique photographs These photographs are taken from a airplane at a angle. Horizon is not visible Advantages They show a larger area Shows much more information Disadvantages Objects in the foreground block out objects in the background Objects in the foreground appear larger than objects in the background

60. LOW OBLIQUE PHOTOGRAPH Taken from an aero plane, horizon not visible.

61. Vertical photographs Taken from a airplane but the camera is tilted vertically down. Advantage No hidden areas Shows a lot of information Used to draw maps Disadvantages Height and surface slopes are not easy to identify A lot of experience is needed to obtain information from these photographs

62. Other Graphical analysis Know how to read and complete the graphs below Bar graphs Line graphs Pie Chart Divided Bar graph Triangular graph Wind rose