Transcript as-geog2-section-a - Geography is easy

AS
GEOG2 SECTION A
Self-quizzing:
I have included questions in this presentation,
followed by mark scheme from AQA.
Some answers are on the following slide.
Some slides include animation-appear- to
show answers to questions.
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CHECK YOUR PENCIL CASE!
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MAP SKILLS
1- maps with located proportional symbols –
squares, circles, semi-circles, bars (see graphical
skills)
2- maps showing movement – flow lines, desire
lines and trip lines
3- choropleth, isoline and dot maps
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Maps showing movement – flow lines, desire lines and trip lines
There are all used on maps to show movement
as either arrows or lines. They can also be used
to show the density of the movement.
1- Flow line map: shows the actual flow and
direction of something (for example traffic). The
flow line is drawn proportional to the number
travelling along the route by the use of a
suitable scale.
See next slide for example of flow line map
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Measuring traffic flows in Manchester
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Desire lines
• Show how busy a route is between two places.
• The line ignores the actual route taken and
simply concentrates on the origin, the
destination and the number on the route.
• Shows movement between region or even
different parts of the world.
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Desire lines
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Trip lines
• Variation on the desire line concept.
• Used to display information related to trips or
journeys taken by individual people.
• On a map, trip lines look like spokes on a wheel
• For example, a series of trip lines could be drawn
our from a central point (such as a supermarket)
to each customer’s home to see the sphere of
influence of the supermarket (the maximum
distance people are prepared to travel to use that
service)
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Flow line
Trip line
Dot maps
• Useful to identify the density of a particular
variable such as population
• Indicate the distribution of a particular
variable
• It is possible to estimate the numbers in a
particular place, provided each dot is clearly
visible
• limitations see next question
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JUN13 : 1 (a) Study Figure 1, a dot map showing the distribution of population in
Brazil.
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1 (a) (i) Using Figure 1, describe the distribution of population in Brazil. (3 marks)
1- Even? Uneven?
2- Highest density?
3- Sparsely populated?
4- Clusters?
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1 (a) (ii) Outline one strength and two weaknesses associated with the dot map for
displaying this data. (3 marks)
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Choropleth maps
These are maps, where areas are shaded
according to a prearranged key, each shading or
colour type representing a range of values.
See strengths and limitations next slide
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Strengths:
• Choropleths give a good visual impression of change
over space.
• Simple technique to use and extremely effective at
helping to observe patterns that would otherwise
remain hidden in numerical data.
• Spatial anomalies can easily be identified.
Limitations:
• They give a false impression of abrupt change at the
boundaries of shaded units. The reality is probably that
change is more gradual.
• Variations within map units are hidden.
• You do not know the actual data at any point of the
choropleth map
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JUN12: 1 (c) Study Figure 3 which shows rainfall data gathered over a period of 72 hours in
November 2009 for part of Britain.
Comment on the usefulness of this technique as a method of displaying this data. (5
marks)
Comment on? On data/stimulus response questions, it means to examine the
stimulus material provided and then make statements about the material and its
content that are relevant, appropriate and geographical, but not directly evident.
For a mapping technique, your answer must include the strengths and limitations of
this technique.
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Isolines
• Represent the same value along their own
length e.g. contour lines on OS maps
• River depth data
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JUN11:1 (b) (i) Study Figure 2, a sketch plan of a meander showing river channel depth.
Add the following information:
an isoline to represent the river depth of 5 cm a label which clearly locates the deep pool.
A curved 5cm isoline must touch the 5s
indicated on the sketch and extend to the
margins. It must also be on the correct
side of the 3s and 6s respectively. A
second mark is available for accuracy
throughout isoline.
For deep pool allow anywhere inside the
25cm isoline.
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1 (b) (ii) Study Figure 3, a sketch cross-section showing velocity along line X—Y in
Figure 2.
Identify with a labelled
arrow the fastest part of the
river and describe the
relationship
between the information
shown in Figure 2 and
Figure 3.
Reserve 1 mark for the fastest part of the river - allow anywhere over 0.4m/sec.
For description allow one mark per valid point with additional credit for
development. For example:
The fastest part of the river also correlates with the deepest. Here speeds of
0.45m/sec appear to be the deepest sections (at up to 32cm depth) (d). This also
appears to be the outside of the bend of the meander (d). As the water becomes
shallow velocity decreases. Additional credit for development. No credit for
straight reversals. Use of data must link Figures 2 and 3
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Graphical Skills
1- line graphs – simple, comparative, compound
and divergent
2- bar graphs – simple, comparative, compound and
divergent
3- scatter graphs – and use of best fit line
4- pie charts and proportional divided circles
5- triangular graphs
6- radial diagrams
7- logarithmic scales
8- dispersion diagrams.
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1- Line graphs
• Simple but effective way of showing
continuous data.
• Useful because they can suggest trends over
time and can be used to estimate future
patterns based on present trends
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Study Figure 1 which shows changes in the populations of
India and China between 2000 and 2050 (projected).
Jun10
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Questions linked to this line graph
1 (a) (ii) Describe the changes shown in Figure 1. (4 marks)
Answer the questions and check your answers
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Compound line graph
On a compound line graph different sets of data
can be displayed to allow comparison to be
made.
(‘Cheese cake’ graph)
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DTM
The DTM is a very specialised comparative line
graph which looks at how changing birth and
death rates impact upon the total population.
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2- bar graphs
• Simplest form to represent numbers in a set of
data
• Can be used either to compare different sets
of data or to compare categories within a set
of data
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JUN 12 QUESTION 1 (d)
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JUN10:Study Figure 5 which shows estimated population change in India’s largest
urban areas between 2008 and 2030.
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1 (c) (ii) Suggest factors responsible for the changing
populations shown in Figure 5. (5 marks)
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1 (c) (ii) Notes for answers (5 marks)
This response does not require specific knowledge of India in order to score full
marks. Any reasonable factors offered can score credit.
Cities are growing for many different reasons for example:
• birth rate is a major factor affecting the growth of cities in India
• rural to urban migration is still an important consideration, with valid reference to
push and pull factors
• improved health care and diet is responsible for lowering the death rate, thus
contributing to overall growth of cities
• some may comment on the larger increases in Kolkata, Delhi and Mumbai, making
links to their regional centre status, attracting further migrants for employment
opportunities.
Level 2 (4-5 marks)
Clearly aware of the urban theme of question. Shows knowledge and understanding of
the factors affecting the growth of cities in such locations. More than one factor
suggested for L2. For full marks must specifically refer to either birth rate or
inward migration.
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JAN11
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1 (a) (ii) Describe the pattern now shown in Figure 1.
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Compound bar graphs
= Divided bars
Individual bars broken down to show more than
one piece of information.
All values are changed into percentage and add
up to 100.
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JAN12: Study Figure 3 which shows three different types of benefit claimed by people in
different areas of Merseyside in 2008.
1 (c) (ii) Using Figure 3, calculate the mean
percentage of Disability Living Allowance
claimants for the four areas now shown. Explain
why the mean is a useful measure for this set of
data. (3 marks)
Mean percentage =
1 (c) (iii) Describe and comment on the
patterns now shown in Figure 3. (5 marks)
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1 (c) (iii) Describe and comment on the patterns now shown in Figure 3. (5 marks)
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1 (c) Study Figure 4 which shows birth rates and death rates for selected countries.
1 (c) (i) Choose an appropriate technique and display the data shown in Figure
4, using the axes provided on the graph paper below. (4 marks) Next slide
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The most likely technique will be a comparative bar chart. Alternative techniques can
be credited if the data is presented appropriately e.g scatter graph. Pie charts and line
graphs are not appropriate.
Accurate and complete data displayed (2 marks)
Appropriate scale (1 mark)
Both axes labelled correctly (1 mark)
Use of key (1 mark)
Lose 1 mark per inaccuracy or omission (Max -2 for inaccurate data presented)
No data presented – No credit awarded
Inappropriate technique e.g line graph –no credit.
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Don’t forget to
add key
Don’t forget to label axes
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Divergent bar graphs
• Graph with data spread on either side of the
x-axis.
• For example: population pyramids
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HOW TO INTERPRETE A POPULATION
PYRAMID
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Question Jun09 1(a)
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3- scatter graphs – and use of best fit line
• Investigate correlations
• Dependent/independent variable?
If one of your variables is expected to affect a
change in the other, the variable affecting the
change is referred as ‘independent’ and this
data is plotted on the x-axis.
The data thought to be affected by the change is
referred to as the ‘dependent variable’ and is
plotted on the y-axis.
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Line of best fit/anomaly
How to draw a line of best fit
Draw a line that broadly represents your pattern
with an equal number of points on either side.
Anomaly or residual
A piece of data which is very different from the
rest.
Generally it is a good practice to ignore it when
drawing the line of best fit
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JUNE 12 : 1 (b) (i) Study Figure 2 which shows the relationship between catchment size
and annual discharge for selected rivers in the north of England in 2009.
1 (b) (ii) Describe the pattern now shown
in Figure 2. (4 marks)
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How it was marked: 1 mark per valid plot (Accept 75 km2 for River X catchment
size) 2×1
1 mark for appropriate best fit line.
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1-State the type of correlation and describe it.
2- Look for clusters of data. Give data
3- Identify anomaly/ies and give data
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4- Pie charts and proportional divided circles
• Various components of whole set of data broken
down and displayed as a series of segments.
• Segments are proportional to each other within
the pie chart.
• A proportional divided circle has its area
proportional to the overall values in the data set.
• These are mainly created for the purpose of
comparing data set.
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How to create a pie chart
• Each category within the data set has to be
turned into a percentage of the set of data. To do
this, divide the segment value by the overall
value and then multiply by 100.
• Each category has to be turned into a number of
degrees. Since there are 360 degrees in a circle,
you need to multiply your percentage by 3.6 to
turn it into a number of degrees.
• Draw a line from the centre of the circle to the
top. Add segments.
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JUN10: Using the information provided in Figure 2 and Figure 3, complete the proportional
divided circle (Figure 4) to show India’s projected population total and structure for
2050.
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1 (b) (ii) Using the information provided in 1(b)(i), describe the
changes to India’s population total and structure. (4 marks)
Answer questions. Check answers next slide
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5- triangular graphs
• 3 variables that add up to 100.
• Useful in showing patterns of clustering
between different variables
• However: triangular graphs only work with a
very limited range of data.
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JAN12 Study Figure 2 which shows population age structures in ten Super Output Areas
in Merseyside.
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To plot data, remember this simple way:
B axis
A axis
X
C axis
B axis
A axis
C axis
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Compare the pattern now shown in Figure 2 with the national average data and
suggest implications for the provision of services in these areas. 8 marks
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6- radial diagrams/Polar graphs
• Polar graphs are a useful technique for
showing data related to change over time or
change in direction.
• However: it slightly distorts the higher values
making it a little difficult to interpret
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JAN13: 1 (a) Study Figure 1 which shows two different traffic flows over an 18-hour
period in Winsford, Cheshire. No data were collected from 00.00 to 05.00.
All vehicles going into and out of the town centre were counted for a period of ten
minutes at the start of each hour.
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2×1 for each accurate plot. Use of key not essential but plots must be joined
up. Maximum 1 if points are not joined. One plot not joined – 0 marks.
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1 (a) (ii) With reference to Figure 1, compare the traffic flows into and out of
the town centre.
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7- logarithmic scales
• Uses a series of cycles where increases occur
in multiple of 10.
• Particularly useful when there is a very large
range of data to display
e.g. Flood frequency analysis and The Hjulstrom
Curve
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JUN11: Study Figure 4, the Hjulström curve.
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1 (c) (iii) Using Figure 4, explain how velocity and particle size
affect the deposition process. (6 marks)
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The Hjulström curve tries to explain the dynamic relationship between
velocity and particle size. The smallest particles held in suspended load may
not be deposited even at the lowest speeds. Above this particle size, at the
lowest river speeds, these particles will be deposited. This is because the
particles change from clay based to silts and are therefore heavier. As particles
become larger they generally become heavier (also changing from sand to
larger materials). Therefore at lower velocities these particles are deposited.
Refer to competence in relation to different river velocities.
Level 2 (Clear) 5-6 marks
Clearly aware of the more complex aspects of the relationship. May refer to key
technical terms such as suspended load. May consider the nature of the load as
particle size increases. Explicit reference to Figure 4.
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8- Dispersion graphs
• Allow you to investigate visually the spread of a
set of data.
• By plotting all of the data set on a vertical axis,
the range within the data set becomes visually
apparent.
• It is also possible to identify any clustering within
the data set.
• To analyse the data further, extreme values may
be removed by using the interquartile range.
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Jan 10
a dispersion diagram showing total rainfall at various weather
stations across England
Questions linked to dispersion graphs
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• 1 (a) (iii) Using Figure 1 and your answers in
1(a)(i) and 1(a)(ii), describe the dispersion of
rainfall in England in 2005. (4 marks)
Answer the questions and check mark scheme
next slide
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Statistical Skills
• measures of central tendency – mean, mode,
median
• measures of dispersion – interquartile range
and standard deviation
• Spearman’s rank correlation test
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Measures of central tendency – mean, mode,
median
Mean/average: you simply add up all the values in
your data set and divide by the number of values in
the set. Heavily influenced by extreme values.
Median: Mid-point of a data set. You have to put all
values in rank order and select the middle value.
Straightforward when there is an odd number of
values. When there is an even number, you have to
total the middle two values and the divide by 2.
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Mode
Refers to the frequency with a data set.
To calculate this you have to note the value that
occurs most frequently in the data set.
You might find that there is more than one
modal value. If there are two modes the correct
term is bi-modal.
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Interquartile range
Requires a formula to work it out.
Takes away any extreme values.
You have to remember the formula:
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a dispersion diagram showing total rainfall at various weather
stations across England
To highest
IQR is often linked to dispersion graphs
See slide 64 for answer
From lowest
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Standard deviation
• Measures dispersion around the mean
• Linked to the normal distribution curve
• σ is added or subtracted from the mean
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Normal distribution curve
It assumes that the data in your
set follows a simple distribution
around the mean.
In a normal distribution:
68.2% of the data should lie
within +/-1 standard deviation of
the mean. (blue area)
95.4% should lie within +/-2
standard deviation of the mean.
(green + pink areas),
99.7% should lie within +/-3
standard deviation of the mean.
(green + pink+ orange areas)
If the standard deviation score shows a normal distribution it means that there are few
extreme values . Therefore the dispersion around the mean is low = low standard deviation.
This makes the mean a more reliable representation of the data.
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JUN11: Rainfall variation in a location over a 12 year period is being
investigated.
A standard deviation calculation has been started in Figure 1.
Complete Figure 1 and then use the formula below Figure 1 to
complete the standard deviation calculation. Do all calculations to
two decimal places.
σ = 103.01
1 (a) (ii) What does your calculated standard deviation value
suggest about rainfall variation at this location?
Assuming the data is normally distributed 68.2% of the data should
lie between 636.6 and 430.58. However, only 57% of the data lies
between 636.6 and 430.58. Therefore, the value of σ is large and
suggests considerable variation (measured against the mean) in
rainfall based upon this sample of data. In this location, some years
are much drier than others (or vice versa).
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Spearman’s rank correlation test
• Measures correlation.
• Indicates the strength of the relationship as a
numerical value.
• Answer should lie between -1 and +1.
• Your answer must exceed the critical value for the test
at the 95 per cent level(0,05 level of significance)=
result was not a statistical chance ,
• Any less than this and you will reject the findings and
accept the null hypothesis.
• Degree of freedom: number of paired measurements.
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Ranking
• If two data or more have the same value, they
are given equal ranking.
• e.g. 1, 2, 3.5, 3.5 (3.5 is the mean of 3 and 4),
5, 7, 7, 7 (7 is the mean of 6,7 and 8), 9, 10.
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JAN11:1 (b) The relationship between the
number of migrants to the UK in 2006 and the
distance between the UK and country of origin is
being investigated.
Here is the null hypothesis:
‘There is no relationship between the number of
migrants to the UK and the distance between
country of origin and the UK.’
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A Spearman’s Rank Correlation test has been
started in Figure 2 below.
Complete Figure 2 and then use the data in the
formula below the table to calculate the value of
rs to three decimal places. Show your working
in the space opposite.
Always check the number of decimal required
in your answer! = 1 mark!
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Coefficient was: −0.042
The result is not statistically significant at either the 0.01 or the
0.05 level
of significance as the coefficient is lower than both critical values
(1) . Therefore, there is no statistical relationship between distance
travelled and number of migrants to the UK (1). The null
hypothesis is accepted.
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June 13: rs = 0.740
The relationship between fertility rate and infant mortality rate in selected Brazilian
states in 2010 is being investigated. The null hypothesis is:
‘There is no relationship between fertility rate and infant mortality rate.’
Answer next slide
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E.g. The rs calculation exceeds the confidence levels at both
the 0.05 and 0.01 level of significance, suggesting a high
probability that the result has not occurred by chance. There
is a strong positive correlation between the fertility rates
and infant mortality rates.
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GIS/ICT in geography
Remotely sensed data, databases and
geographical information systems (GIS) are
examples of how ICT can be used in geography.
Explain how the use of ICT can improve
geographical understanding.
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The response depends upon the chosen applications. The
specification makes reference to remotely sensed data,
databases and geographical information systems (GIS).
Candidates are not limited to these ICT applications and may
also refer to programmes such as Excel.
Databases such as The Met Office provide a vast amount of
information allowing for detailed analysis of rainfall and other
weather patterns. This allows for comparison between areas
as well as predicting the impact of particular events. This is
useful for both river field studies as well as theoretical
examination of river processes and flooding. Such databases
can also be used to support case studies as well as providing
the basis for field investigations.
Level 2 (Clear) 4-5 marks
May lack breadth but clearly focused upon the benefits of ICT
applications. Clear links to improving geographical
understanding. More sophisticated understanding of the
benefits linked to geographical outcomes.
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