Links for quantities and units

[SiBell]

Could do with adding a quick guide detailing where to find existing dictionaries of quantities and units. The hope being that the values we set for observedProperty and unit in our JSON-LD responses match those from other observatories.

I assume the main source of vocabulary would be QUDT, but it's not the easiest to search through.

[lukeshope]

Agreed. I also think QUDT has some omissions, especially in the context of air quality. Could you add to this list with anything slightly unusual you can think of so we can try find a good example for each?

• Air quality
  • Gas concentrations (ug/m3)
  • Gas concentrations (ppm/ppb)
  • Particle counts
• Water quality
  • Concentrations (mg/l)
  • Turbidity (NTU)
  • FDOM (quinine sulphate units)
  • Specific conductance (uS/cm)
• Climate
  • Air temperature
  • Precipitation intensity
  • Precipitation accumulation
  • Relative humidity
  • Wind speed
  • Wind direction
  • Soil temperature at depths
  • Station level atmospheric pressure
  • Mean sea level pressure
  • Lightning
• Counting
  • Vehicle and pedestrian counts
  • Directions of travel
• Other environmental
  • Noise levels
  • Light levels
• Infrastructure
  • Rail head moisture
  • Rail web temperature
  • Road surface temperature

[SiBell]

Updated. Probably worth asking the other observatories too.

[EttoreHector]

Hi Luke and Simon.

As you already pointed out there are some omissions in QUDT, for example the typical concentration unit of pollutant level "micrograms per cubic meter". How do we go around this? My understanding is that we have to define the new unit in terms of the "more standard" units present in QUDT (for example we'd have to define ug/m3 in terms of kg/m3). Is this correct? And if it is do you know how to proceed?

[lukeshope]

Hi Ettore,

We can define our own vocabulary if necessary. We would need to define a namespace for it and then describe the terms with some heirarchy and descriptions. As examples, the W3C SSN is defined in Turtle and the Hydra Core is defined in JSON-LD. I presume we'd prefer to use the latter.

I still find it hard to believe there's no vocabulary out there already that defines micrograms per cubic metre, but I also haven't found one. Crazy...

I think we'll need to define a handful of our own vocabulary terms as a minimum anyway.

[lukeshope]

Closing this because units are now being discussed alongside observedProperty types in #23.