Please add units of gas concentration of semantic and degree unit of the semantic's Angle

[Lin-YenYu-sysinno]

We read the digital twins list about semantic type. We feel this list doesn't match any unit for gas concentration.

When measuring gases like carbon dioxide, oxygen, or methane, the term concentration is used to describe the amount of gas by volume in the air.

The 3 most common units of measurement are parts-per-million, parts-per-billion, and percent concentration. And the term concentration is used to describe the amount of gas by mass in the air.

The Density of semantic types is kilogram Per Cubic Metre. That is bigger than the regular mass of the gas concentration.

The most mass common units of measurement are milligram per cubic meter and microgram per cubic meter for the mass of the gas concentration.

so I make the summary for this issue.
We need you to add the gas concentration of semantic type and five gas units.

• parts per million.
• parts per billion.
• unit percent.
• milligram per cubic meter.
• microgram per cubic meter.

I also need to add the degree unit in the semantic's Angle.

[briancr-ms]

Thanks for your request. We're looking at enabling you to be able to add your own units (along with your own semantic types). I'll keep this issue open until we have a design to share.

[maurert]

Any progress? I noticed inchesOfWater exists but not centimetreOfWater. There are more cases with similar issues.

[rido-min]

We have published the DTDL v3 preview, which includes new Semantic Types https://github.com/Azure/opendigitaltwins-dtdl/blob/master/DTDL/Docs/en-US/DTDL.quantitativeTypes.v1.md including Concentration.

Does this new type solve your request? If so, can you close this issue?