Ranges and Strong Typing of Measurement Values

[jmkeil]

I suggest the following changes to OM:

• where possible change datatype of om:hasNumericValue literals from xsd:string to xsd:decimal (including transformation of lexical representation) (45e8b68)
• add properties om:hasNumericalValueGreaterOrEqual & om:hasNumericalValueLessOrEqual (0ec8d63 and ec49024)
• apply om:hasNumericalValueGreaterOrEqual & om:hasNumericalValueLessOrEqualto existing approximate values (0ec8d63)
• set range of om:hasValue to xsd:decimal (6e7e878)

This will enable

1. the machine readable definition of approximate values or ranges, and
2. a strong typing of numerical values making OM easier to use, as software/queries can make more assumptions on the literals to expect.

om:hasNumericalValueGreaterOrEqual & om:hasNumericalValueLessOrEqualare defined as super property of om:hasNumericValue. That way,

_:a om:hasNumericValue 1.0 .

entails:

_:a om:hasNumericalValueGreaterOrEqual 1.0 .
_:a om:hasNumericalValueLessOrEqual1.0 .