Page 106 - The World About Us

Millet seed heads
Gunung Leuser
1.1.1
1.1.1
1.1.1
1.1.1
2.2.33.3
2.2.3

Cross-sections Numerical skills in Geography?
These are useful for showing
changes in relief along a straight line Geographers use a range of 1.588498732 mes larger than the UK.
or ‘transect’. They can be used to numerical and sta s cal skills to This is be er wri en as ‘Norway is
show the shape of a river valley, interpret and analyse data. We use about 1½ mes larger than the UK’. The
glacial trough or the shape of a river these skills to inform our conclusions. precision to so many decimal places is
channel. The ver cal x axis should be not necessary. Mawsynram receives
There are a number of basic, but
drawn with the same scale as the 13,692 mes more rain than Egypt's
vitally important, numerical skills
horizontal y axis. The cross-sec on Aswan. This would be be er wri en
essen al to good geography.
below uses measurements taken with the actual or rounded figures:
across a small river channel. Area, scale and ratio Mawsynram receives an average
depth (m) 0 1 helps us with concepts such as space, 11,871 mm of rainfall while Aswan
Area is a very important concept. It
receives less than 1mm each year.
2
5
4
3
1
0
width (m) 6 7 8 9
place and density. Area is calculated by Frequency refers to how o en or
Rose graphs mul plying the length of a space by its regularly something occurs. This can
Rose graphs are used to display width. On Ordnance Survey maps each be given as a direct number per
data around a circular axis. They are grid square represents one square specified me frame, eg. there have
good for showing data linked to kilometre. The area of the square is been fi een major volcanic erup ons
compass direc ons or me. The rose linked to the concept of scale. in Indonesia since 1850. This could also
diagram below shows traffic flow on Maps represent a plan view of the be given as a mean frequency of one
the B6472 near Bolton, recorded over world, presented at a different scale to erup on every 11 years and 56 days.
the 24 hours of a single day. When reality. The scale of the map refers to However, by changing the mescale, it
deciding to use a rose diagram, it is the rela onship between the distance is possible to change the frequency.
always best to see if the data is easier shown on the paper and its actual Since there were 7 major erup ons
to read as a simple line graph. Radar distance in the real world. On a between 1950 and 2000 the mean
graphs may look 'fancier' but they 1:25,000 OS map, 1 cm is equal to frequency for those fi y years was one
may confuse rather than illuminate. 25,000cm, 250m or 0.25km. Since a erup on every 7 years and 52 days.
00:00 grid square on this map is 4cm across,
23 350 01 Time Central tendency & averages
22 02 the square represents 4 x 25,000cm:
300
vehicles
21 250 03 100,000cm is equal to 1000m or 1km. The central tendency of a data set
20 200 04 is commonly referred to as the
150 A grid square on a 1:50,000 map is
19 100 05 only 2cm, so the scale is double the average. It represents the central point
50 within the data. This can be reached by
18 06 1:25,000. 2cm is equal to 100,000cm, several methods.
1,000 metres or 1km in the real world.
17 07 The mean, which is what most
Ra o or propor on can also be
16 08 people associate with the term
used to describe informa on and give it
15 09 a context. For example, 1 in every 2 kg ‘average’, is calculated by adding up all
14 10 the data in the set and then dividing by
13 10 of palm oil is produced in Indonesia.
12:00 the number of data values. GNI per
Traffic away from Bolton This is equivalent to 50% (1 ÷ 2 x 100)
Traffic towards Bolton of global produc on. capita is a mean; it takes the total
income of the country and divides it by
Wind rose charts Magnitude the total number of people.
Wind rose diagrams are rose graphs Magnitude is used to describe the Median describes the middle value
used to show how wind direc on and rela ve size of one thing to another. of the data, once the data has been
strength varies over me. For example, the area of the world’s placed in a rank order.
N
oceans is 3½ mes greater than the The mode describes the most
Wind speed land area. These descrip ons are a commonly occurring value: the number
m/s NW NE
>11.0 useful shorthand for comparing rela ve that appears most frequently within
12%
8.4 -11.0 9% sizes of features in the same loca on. the data.
6%
5.4 - 8.4 However, if the level of detail is too
3% If there is a large amount of data it
3.4 - 5.4 W E great or the scale of magnitude too may be a good idea to create classes of
1.8 - 3.4
large, a magnitude descrip on may data. The modal class is the one with
<1.8
cause more confusion than clarity. For the greatest number of data sets within
example, the area of Norway is it, it may not contain the actual mode.
SW SE
S
106

Geographical skills.