A graph with one column where data is spread out over the one axis.
- Can work out range, median, mode, lower quartile, upper quartile and interquartile range.
- Anomalies are shown easily.
- Shows how reliable the data is.
- Can work out the standard deviation.
- Works better with a lot of data.
- Standard deviation can be manipulated.
Shows how a variable changes due to an independent variable e.g. wind direction changes.
- Can compare lots of sets of data.
- Individual variables within the diagram can be compared.
- Hard to spot anomalies.
- Hard to make scale suitable.
Often used to show quantity of plant species and how they vary with distance as the wider the data points means that the more common they are.
- Clear and easy to understand.
- Shows changes over distance (bedload).
- Shows density and distribution of variables.
- Not all data can be represented by these charts.
- Time consuming to plot by hand.
Out of 100% these a breakup of data into a percentage of the total which is then shown by segments on the pie chart.
- Allows fractional and percentage comparison.
- Visual - can see a general.
- Display approximate variations.
- May not be accurate.
- Can't represent more than one point at a time.
Line graphs & bar charts
Where a variable is plotted against an independant variable e.g. rainfall against location.
- Comparisons can be made easily.
- Anomalies are clear.
- Shows general trend.
- Can be tedious and time consuming.
- Can often require additional data for them to be useful.
Shows distribution over an area.
- Shows variation and pattern.
- Easy to interpret.
- Effective in showing spatial density.
- Actual values can't be seen.
- Time consuming if done by hand.
- Easy to make a mistake.
Allows 3 proportional variables out of 100% to be plotted against each other.
- Easy to compare.
- 3 bits of data can be compared at the same time.
- Difficult to construct.
- May be interpreted wrong.
- Difficult to read - need background knowledge to understand.
Where the size of the circle shows the population of data, often for one area.
- Can represent large range of data.
- Not dependent on size of an area.
- Difficult to produce.
- Not accurate / can't extract data.
- Overlap can make it confusing to read.
Indicate a line of movement with its thickness representing the volume of movement and direction the line of flow.
- Immediate impression - can tell general trend.
- Gives clear sense of direction.
- Shows movements easily.
- Hard to draw.
- Flows can overlap.
Uses colour overlay over a map to show how an area fits into a range of values, often with darker values representing the higher values and lighter for the lower values.
- Gives general trend easily.
- General anomalies can be identified.
- Easily done by hand.
- Too general.
- Reading exact figures is impossible.
- Variations within each area are hidden.
Where data points on a map are joined up with data points of equal values e.g. contour lines.
- Can see gradual changes.
- Can see areas of equal value.
- Drawn easily on computers.
- Small lines and numbers on graphs may be difficult to read.
- Does not show continuous distributions.
- Only works when changes are gradual.