A dimension is a means of summarising information by grouping it into sets. Dimensions describe their constituent sets consistently and efficiently, and therefore provide an ideal approach to analysing large amounts of data.
MAST dimensions are used to process raw data into measures stored in data cubes, so a large amount of information is readily available to users. They are also exposed for use as categories, series and filters in MAST reports.
Dimension Structure - Hierarchies
A hierarchy is organised into a structure of several levels, each containing a collection of sets. Hierarchies are organised in a similar way to family trees, so every set at each level is grouped within one of those at the level above. They generally have a single top level set, which includes all items in all the levels and categories beneath it.
Most MAST dimensions contain only one hierarchy, but some contain more if there are different ways in which that dimension's data could meaningfully be organised. Examples of this include the Conditions - Light and Conditions - Weather dimensions.
Dimensions in MAST
MAST uses dimensions as a way of organising road safety and demographic data.
Other dimensions commonly used in MAST include:
- Dimensions based on the Geography hierarchy, which can apply to:
- Dimensions based on the Severity hierarchy, which can be applied both to casualties and to crashes
- Dimensions based on Mosaic classification, which can apply to:
- Dimensions based on the Age and Gender hierarchies, which can apply to both casualties and involved drivers
- Vehicle Type