Graphical Skills:
Bar Graphs and Line Graphs:
Simple line graphs are drawn to show a single series of data
Comparative line graphs show two or more sets of data on the same graph. The lines are drawn using the same scales on the x and y axis
Compound line graphs are drawn with several different components, which will add up to a total amount e.g. production from different energy sources
Simple bar graphs show a single series of data
Comparative bar graphs show two or more sets of data. The columns for each division along the x-axis are drawn side by side
Compound bar graphs show how the total in any one bar is divided up between a number of subtotals
Divergent bar graphs might start as simple bar graphs but then become compound bar graphs when subtotals become available
Scatter Graphs:
Scatter graphs show the relationship between two sets of variables. They're designed to show:

• positive relationships, where as one variable increases so does the other
• negative relationships, where as one variable increases the other decreases
• no relationship, where there's no pattern and the points seem to be distributed at random

If a relationship is shown by the graph, it is possible to see whether the relationship is a strong or weak one. This can be demonstrated by drawing a line of best fit though the centre of the distribution of points
If most points are close to the line, the relationship is strong; if they're far away from the line, the relationship is weak. These judgements are subjective, so if a relationship is suspected it's often useful to carry out a Spearman's rank
Scatter graphs allow for presentation as well as analysis of data (by the use of the line of best fit)
Pie Charts & Proportional Circles:
Pie charts are used for showing how a total is divided up into separate components. Each sector represents one component and its size shows what proportion that component contributes to the whole
Proportional circles are used when the size of two totals is being compared. Then the area of the circle represents the total, with bigger circles representing bigger totals
Proportional circles can also be divided into pie charts, to show two sets of data presentation for different sets of data at once
Triangular Graphs:
This is essentially a scatter graph that shows three sets of variables and allows the user to see how those variables are interrelated
They're often used to plot:

• employment structures, when employment is divided into primary, secondary and tertiary
• soil structure where the percentages of sand, silt and clay particles are given

Kite Diagrams:
These are usually plotted to describe the distribution of different species along a transect line e.g. different species along a transect line
The 'kites' represent the presence or abundance of individual species along the line of transect, measured using a quadrat. The thickness of the kite shows the number or %age of each species at each survey point
Radial Diagrams:
They use 'polar coordinate' graph paper and can be used to show:

• orientations as given by the points on a compass; diagrams like this are often used for showing the orientation of particles in glacial deposits, so the direction of ice flow can be worked out
• continuous cycles, such as daily or annual progressions (e.g. temperature changes)

Logarithmic Scale Graphs:
These are used in two main sets of circumstances:

• when a very large range of data must be shown and when those data would make an arithmetic graph difficult to draw and unclear to read
• when an arithmetic graph would result in a parabolic relationship but when a log graph would show a much clearer straight-line relationship

An example of this using semi-logarithmic graph paper is to show the changes in the size of the populations of various continents
Fully logarithmic graph paper is often used to show the relationship between the area of the a drainage basin and the length of the stream in that basin
Dispersion Diagrams:
These are used to show the spread of a number of values around the mean value, enabling a comparison of the spread and/or bunching of data
They're often used as a prelude to a stats technique, such as calculation of median, upper and lower quartile and standard deviation