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OS MasterMap technical information - data measures

This table gives you the generic definitions of the ways we measure the data in our products.

Data Measure Definition Sub-measure Definition
Completeness Presence and absence of features against the specified data content Omission Features representing objects that conform to the specified data content but are not present in the data
Commission Features representing objects that do not conform to the specified data content but are present in the data
Logical consistency Degree of adherence to logical rules of data structure, attribution and relationships Conceptual consistency How closely the data follows the conceptual rules (or model)
Domain consistency How closely the data values in the dataset match the range of values in the dataset specification
Format consistency The physical structure (syntax): How closely the data stored and delivered fits the database schema and agreed supply
Topological consistency The explicit topological references between features (connectivity)- according to specification
Positional accuracy Accuracy of the position of features Absolute accuracy How closely the coordinates of a point in the dataset agree with the coordinates of the same point on the ground (in the British National Grid reference system)
Relative accuracy Positional consistency of a data point or feature in relation to other local data points or features within the same or another reference dataset
Geometric fidelity The ‘trueness’ of features to the shapes and alignments of the objects they represent
Temporal accuracy Accuracy of temporal attributes and temporal relationships of features Temporal consistency How well ordered events are recorded in the dataset (Lifecycles)
Temporal validity (Currency) Validity of data with respect to time: The amount of real-world change that has been incorporated in the dataset that is scheduled for capture under current specifications
Thematic accuracy (Attribute accuracy) Classification of features and their attributes Classification correctness How accurately the attributes within the dataset record the information about objects
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