GRAPHS AND CHARTS- geographical skills
Bar graph
each bar same width but vary in length, can be vertical, horizontal and divided.
divided- multiple values shown in one bar
Histograms
pros- good visual representation, easy to construct and interpret.
cons- can only use with discrete data, not much space to label categories.
type of bar graph where categories have a range of numbers ie a range of ages, no gaps between each bar.
pros- good visual representation of data, easy to construct and interpret.
cons- not much space to label categories
Line graphs
used to show points joined by a line ie temperatures over a given number of years.
pros-
useful for things like temperatures which don't jump from one value to the next and can be shown on a continuous line.
easy to compare more than one set of data
lines show possible data between specific values
cons- can only use with continuous data
scatter graphs
show relationship between sets of data, show negative or positive correlation or none.
pros-
shows a correlation which can be used to compare data sets.
easy to construct
anomalies easy to spot
cons-
too few data points give unreliable correlation
too many data points make graph unreadable
can only show relationship between two variables
Dispersion graphs
plotted data to see a pattern in the distribution of it. each value is a individual point against y axis, two sets of data on one graph to compare them.
used to plot median, upper quartile, lower quartile and inter- quartile range.
pros-
easy to see patterns and show the spread from the mean.
good for comparisons
anomalies are shown
cons- need to use data that can be placed along a number line.
Pie charts
to draw one- multiply each percentage by 3.6 to convert it into degrees, use protractor to draw figures, label or use a key, add title.
pros-
good for percentages
visual
easy to construct and interpret
cons-
too many segments make graph difficult to interpret
no specific numerical data unless its labeled
Climate graphs
shows average temperatures and rainfall for place during a year- months on x axis and rain and temp on the y axis either side.
proportional symbols
Pros
Cons
Good visual
Scale needs to be accurate
Pictograms
Pros
Cons
Easy to construct and interpret
Good visual representation of data
Doesn't provide specific numeral data
Cross-section
Cons
Pros
Shows a view of a segment
Only one moment in time so many may not be representative
Population
Pros
Cons
Shows the number of people in a range of cohorts (age groups)
Shows how population is composed.
Shows the population structure of country and allows for long-term planning as relative sizes of each cohort will reduce unless significant change in birth/death rate.
General shape can indicate type of population structure.
Can only use for population structure
Figures broken into age categories so some detail may be lost within them.
Radial and rose charts
Pros
Cons
When one variable is to do with directions, e.g. point of compass
Rose chart - type of radial, used to show both direction and frequency of wind
Can only be used with specific types of data
Shows several different sets of data at once.
When one variable is to do with time, e.g. showing flow of traffic over period time.
Good visual representation of data
Hard to spot anomalies
Proportion, ratio, magnitude & frequency
Number, area and scale
Central tendency, spread and cumulative frequency
Percentages and percentiles
Area
Scale
Number
Measured in square units - length of area x width
Fieldwork data sheets, collecting data & drawing informed conclusions from numeral data
Scale of map refers to how specific area relates to real life distance
Magnitude - relative size of something, mostly used about impact of earthquake. Measurement of energy released by earth. Also by used in relation to settlements.
Frequency - how often something happens
Proportion - built from ratios.
Ratio - comparison between 2 things.
Mode - most frequent occurring number. If large amount of data sort into classes, class with highest frequency, with most values is model class
Range - difference between highest and lowest value.
Mean - add up all value divide by how many there are
Inter-quartile range - shows spread of data, more accurate than range. 25%, 50%, 75%
Median - middle set of data.
Divide the increase by first number
Multiply answers by 100
Work out difference between numbers
If answer a positive number = percentage increase - if negative percentage decrease
To work out percentage;