Properties of type quantity are used to store a numerical values together with the scientific unit of measure. The value of a quantity is its magnitude expressed as the product of a number and a unit, and the number multiplying the unit is the numerical value of the quantity expressed in that unit.
Therefore the value of a quantity type property consists of two parts: the numerical part and the unit part. The quantity property type allows for unambiguous storage exchange and processing of numeric data. Numerical data can be stored in different units of measure and the Application Server provides the possibility to convert between different units of measure. See the chapter Quantities for details on how the Application Server handles quantity values.
The numerical part of the value of a quantity property is a double precision number in the range of -1.79E+308 to -2.23E-308, 0 and 2.23E-308 to 1.79E+308, and is internally stored in binary64 floating point format (see IEEE 754). While floating point representation will be sufficient for nearly every numerical value generated by an observation you should still be aware of the fundamental limits of floating point representations.
Each property of type quantity is of a predefined physical quantity (e.g. length, electric current, force, ...) and for each physical quantity the Application Server supports different units of measures. The unit part of the value of a quantity property is therefore one of the units supported for the physical quantity of for the property.
Internally the Application Server always stores the property value as given by the user, i.e. the Application Server does not convert values internally, unit conversion (if needed) is only done when processing or presenting data. Note that whenever unit conversion takes place there is a chance of rounding errors.
Display settings
Display setting |
Description |
Precision |
Number of digit after comma that are actually displayed to the user. E.g. actual precision can be 5 digits after comma, but in a certain context it may be reduced to 3. |
Scientific format |
Defines if the value is displayed in scientific notation. |
Table 1: Additionally supported display settings for this property type
Default value
Default value can be any numeric value in the range of of - 1.79E+308 to -2.23E-308, 0 and 2.23E-308 to 1.79E+308 and any valid unit for the quantity type of the property.
Validation rules
Validation rules |
Description |
Minimum value |
Minimum value in the given unit that can be stored with this property. |
Maximum value |
Maximum value in the given unit that can be stored with this property |
Table 2: Supported validation rules
