Stage 5: Presenting data collected in appropriate forms

Common forms of data

• discrete data - data with distinct parts e.g. crop yield
• ordinal data - data that has an order e.g. ranked data
• continuous data - data where there are no breaks but instead something happens continuously e.g. temperature
• areal data - data that applies to an area rather than a point or individual e.g. population per km2
• time - series data - data where something occurs at intervals e.g. rainfall
• period data - data where a phenomenon repeats itself at intervals e.g. census returns

Selecting a technique

• What to consider when selecting a technique
• Scale/ interval - if too big will hide patterns
• Location - where should figure be placed to best represent area/feature to which it applies?
• Size of symbol - symbols too large may hide information on the map
• Shading - shading should always get darker as values increase, white implies no data
• Colour - colour best avoided as it is difficult to compare different colours e.g. is blue denser than green?
• Lettering - varies in alignment, size, spacing and style, must not obscure other data and should be capable of easily read
• Dimension -
• Key - all maps and diagrams should have a clear key, locate it at bottom right of maps and/ or diagrams
• Legend or caption - all diagrams, maps etc should have a title and a figure number
• Scale - all maps should have a scale

Non spatial displays of data

• TABLES
• USE
• Simple but effective way to show the raw data collected
• Good way of showing a large amount of data in a concise way
• LIMIITATIONS
• Limited visual impact
• DIAGRAMS
• Pictograms uses pictures or symbols to represent the values of the data
• LIMITATIONS
• Easily exaggerated or distorted

CHARTS

• BAR CHARTS
• USE
• Used for most types of data but especially discrete or time series data such as rainfall, pedestrian counts, numbers of services. They are simple, quick and give instant visual impression. Can be horizontal or vertical. Length of the bar is proportional to its value.
• LIMITATIONSWidth of bar can mislead over the value represented by the bar. Gaps should be left between the bars otherwise it is known as a histogram.
• PIE CHARTS
• USE
• Used with percentage data to show the constituent parts of a whole.
• Visual
• LIMITATIONS
• Too many sectors can be silly
• Difficult to use colours as these distract from sector size
• Difficult to label so all sectors can be easily read
• Can only use it for percentage data

GRAPHS

• Normally refers to line graphs, but can apply to scatter graphs or cumulative frequency graphs
• USE
• Ideal for continuous data or looking at patterns/ trends between two or more variables
• line graph
• scatter graph
• multiple line graph
• triangular graph
• compound line graph
• positive and negative graph

SPATIAL DISPLAYS OF DATA

• MAPS E.G. ORDANANCE SURVEY MAPS
• ISOPLETHS OR ISOLINES - LINES THAT REPRESENT THE SAME VALUE AT THE POINTS IN AN AREA THROUGH WHICH IT PASSES
• LIMITATIONSselection of the interval value between isopleths is crucial
• you need to consider the shape and size of the units for which data is available, the scale of the map is critical
• the value interval that you use for plotting your data is crucial
• colours difficult to use so should be avoided
• CHLOROPLETHS - are density maps where areas are shaded in to represent the avg. number per unit area. It gives a quick visual impression of patterns
• LIMITATIONS
• treats the area as a whole so hides variations within the area
• colours difficult to use so should be avoided

PICTORIAL DISPLAYS OF DATA

• SKETCHES - USEFUL WAY OF RECORDING AN IMPRESSION OF AN AREA AS WELL AS SHOWING ITS MAIN FEATURES
• PHOTOGRAPHS - USEFUL TO SET CONTEXTS SUCH AS SHOWING THE FLOW AND LOAD OF A RIVER AT A PARTICULAR LOCATION. MUST BE ANNOTATED TO BE EFFECTIVE