live: final exam preparation p2 29 october …...exam questions question 1 area = length x breadth =...
TRANSCRIPT
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LIVE: FINAL EXAM PREPARATION P2 29 OCTOBER 2014
Lesson Description
In this lesson we revise:
The interpretation and analysis of topographic maps
Calculating: o Area o Magnetic Bearing o Grid Reference / Exact Position / Coordinates o Average Gradient o Vertical Exaggeration
Drawing a cross section
Summary
GIS Questions
Know and remember your terminology and concepts.
Always refer to the map and photograph when answering applied GIS questions
GIS questions can bring knowledge about theory on a very elementary level
E.g. the climate of an area (climatology) the general gradient is a gentle slope (geomorphology), the human and social factors of location (settlement) and the economic impacts of development in a specific place (economic geography)
Exam Questions
Refer to the Topographical Map of Parys.
Question 1
Calculate the AREA of Block C2 on the Topographical Map of Parys
Question 2
Calculate the MAGNETIC BEARING of Δ31 [E3] from Δ706 [C2] for the present year
Question 3
Calculate the GRID REFERENCE/EXACT POSITION/ COORDINATES of Δ706 in [C2]
Question 4
4.1 Calculate the Average Gradient between Δ31 [E3] and Δ706 [C2]
4.2 Explain the ratio
4.3 Is this gradient steep or gentle
Question 5
5.1 Draw a Cross Section between point A and point B on the contour sketch map.
5.2 Calculate the Vertical Exaggeration
NB: The vertical exaggeration is the amount by which the vertical scale of a cross section is larger than the horizontal scale
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Answers
Exam Questions
Question 1
Area = Length X Breadth
= (37mm X 0,05) (33mm X 0,05)
= (1.85km) (1.65km)
= 3.05km²
Question 2
True Bearing = 170º SSE
Mean Magnetic Declination (2001) = 23,7º West of True North
Mean Annual Change = 3 ` westwards
Year = 2001
Number of years = 2014 – 2001
= 13 years
Total Change = 13 years X 3 ` westwards
= 39`
= 0º39`
Magnetic Declination (2014) = 23,7º + 0º39`
= 23º42` + 0º 39`
= 23º81`
= 24º21`
Magnetic Bearing = True Bearing + Magnetic Declination
= 170º + 24º21`
= 194º21`
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Question 3
Step 1 – Determine the latitudinal (latitude) coordinates
26º 54` S
Step 2 – Determine the longitudinal (longitude) coordinates
27º 24` E
Step 3 – Calculate the distance and time between the point and the line of latitude directly above
= 23mm X 60``
37mm X 1
= 37 `` ... Latitude is 26º 54`37``S
Step 4 – Calculate the distance and time between the point and the line of longitude directly to the left
= 26mm X 60``
31mm X 1
= 50`` ... Longitude is 27º 24`50``E
Question 4
4.1
Gradient = Vertical Interval
Horizontal elevation/equivalent
Vertical Interval = (Difference in Height between the TWO points)
= 1456, 4m – 1390,1m
= 66,3m
Horizontal elevation/equivalent = (The distance between the TWO points)
= 73 mm X 0.05 (convert to km)
= 3.65 km (convert to m)
= 3650m
Substitute into the formula
= 63,3 63,3
3650 63.3
= 1
57,66
= 1 : 56,66
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4.2 For every 56,66m in horizontal elevation, gradient increases by 1m
4.3 The average gradient is steep
Question 5
5.1
Step 1:
Step 2:
Step 3:
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Step 4:
5.2 VE (Vertical Exaggeration) = VS (Vertical Scale)
HS (Horizontal Scale)
Step 1 – Determine the Vertical Scale
... is the scale on the y- axis
... 1 cm = 40 m
... convert 40m to cm (x 1000)
... the ratio is 1cm: 4000cm
Step 2 – Determine the Horizontal Scale
... is the scale on the x-axis
... 1cm : 50 000 cm
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Substitute into the formula
= 1 : 4000
1 : 50 000
= 1
4000
1
50 000
= 1 50 000
4000 1
= 50 000
4000
= 12,5 times