Page 104 - The World About Us

Millet seed heads
Rice and cat
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2.2.3
2.2.33.2
How can we use graphs and charts in Geography?
Geography does not just rely on
maps and diagrams to relay
informa on but also uses a range of
graphs and charts. These graphs and
charts are used because they can
o en present lots of data in a
rela vely simple and accessible way.
Pa erns can emerge visually in a
way that is unlikely to happen if data
was simply displayed in a table or
list. The human mind is very astute at
iden fying pa erns in the natural
world and the same is true of
recognising pa erns displayed using
graphs and charts.
Bar Graphs
Fig.269 Employment in Indonesia.
Employment by sector
130
Agriculture
120
Manufacturing
110
Services
100
90
Total workforce (millions) 70
80
60
50
40
30
20
10
0 totals can be shown as actual
1965 1995 2015
Bar graphs are a very common
way of showing data with varying
values. The bars are drawn with equal
width but with a length propor onal
to the data they are presen ng. The
propor on is shown on the axis
legend. Bar graphs are easy to
understand and easy to construct.
Horizontal bar graphs: these bar
graphs have columns which go from
le to right from a ver cal axis (see
figure 102 on page 40).
Ver cal bar graphs: probably the
most common of bar graphs, these
have columns which rise from a
horizontal axis. For example, see
104
Geographical skills.
Indonesia’s imports and exports in The shape of the pyramid is o en
figures 126 and 127 on page 47. a good guide to the stage of social
Divided bar graphs: these bar and economic development of a
graphs can show how a total is sub- country. Wide-based, triangular-
divided, perhaps into percentages. shalped graphs indicate high birth
The bar chart in figure 269 takes the rates and high rates of mortality.
same data on Indonesia’s labour force Narrow-based, bullet-shaped graphs
shown on page 47 as pie charts and indicate low fer lity rates and low
displays it as a divided bar chart. mortality rates.
Histograms Line graphs
Histograms look like bar graphs Line graphs are very useful for
but there are no spaces between the looking at con nuous data that moves
columns. This is because the columns up and down, perhaps over me or
represent ranges in the data which distance. The line graphs on page 73
for global temperatures are very
are connected, such as age groups in
useful at showing the trends over
a popula on. The columns in a
histogram can be different widths if me. Line graphs can be very
persuasive when displaying big
the data sets have different group
changes in data. Look, for example at
values. For example, a 0-20 age group
the line graph for fossil fuel carbon
could be shown as twice the width as
a 20-30 age group. emissions since 1900 (fig.215, p.79).
The line on the graph connects
Population pyramids. known data points. In addi on, the
show the popula on structure of a suggest possible informa on along
Popula on pyramids are used to
path of the line can be used to
the line between data points.
place, usually a country or city. The
popula on is divided by age (usually
Line graphs can be combined with
into five year age groups) and by
trend lines to indicate the general
gender. The data is displayed as two
pa ern or direc on of change within
a central axis; males on one side and
Fig.271 Line graphs and trend lines.
females on the other. The popula on
horizontal histograms diverging from the data.
Data lines
numbers or as percentages of the
Upward trend
whole popula on. Either methods will
give the same shape to the 'pyramid'.
Figure 270 below shows the Downward trend
popula on structure for Indonesia. Trend lines
Fig.270 Popula on structure: Indonesia.
95+ Climate Graphs
85-90
80-85
75-80 Climate graphs describe the
70-75
65-70 temperature and rainfall of a loca on.
60-65
55-60 They combine both a line graph in red
50-55
45-50 for mean temperature and a
40-45
35-40 histogram in blue for average monthly
30-35
25-30 rainfall. Months of the year are shown
20-25 along the x axis. Rainfall in mm and
15-20 temperature in C are shown on the y
10-15
5-10
0-5 axes, usually on opposite sides of the
12 9 6 3 0 0 3 6 9 12 graph for clarity.
Popula on by age group (millions)