Upgrade ODM2_Units from list to full-featured CV w/ SKOS and community

[aufdenkampe]

@horsburgh and @jcaraballo17, I would like to prioritize the upgrade of the ODM2_Units list (http://vocabulary.odm2.org/units/) to a full-featured Controlled Vocabulary, similar to UnitsType (http://vocabulary.odm2.org/unitstype/). Please use WPF Monitor My Watershed funding for this, as we need this functionality in the next month or two to support a simple unit conversion system that Azavea is developing.

In addition to adding a URI for every Unit term, adopting our term syntax convention, enabling SKOS and enabling community capabilities to suggest edits and additions, a full-featured CV would also include extra important fields, such as Definition, ConversionMultiplier, and ConversionOffset. These additional fields are provided in the ODM2_UnitsTable-Combined-QUDT-CUAHSI Google Doc, in the To Transfer to Online System tab.

Finally, this upgrade will address several other pending issues in this repo, including:

• Add ability to request new units. https://github.com/ODM2/ODM2ControlledVocabularies/issues/31
• Add dose equivalent units for ultraviolet radiation dose. https://github.com/ODM2/ODM2ControlledVocabularies/issues/32
• Add example field for requesting new units. https://github.com/ODM2/ODM2ControlledVocabularies/issues/13

And it could provide additional capabilities for ODM2RESTfulWebServices (see https://github.com/ODM2/ODM2RESTfulWebServices/issues/43).

cc. @SRGDamia1 , @emiliom, @lsetiawan

[aufdenkampe]

Here's the issue for Monitor My Watershed: https://github.com/WikiWatershed/model-my-watershed/issues/2588

[horsburgh]

@aufdenkampe - I think we need to discuss this one. It's not a trivial thing, and there's reasons why we decided that Units were not going to be a CV for ODM2. We would also have to look at how it fits with our existing scope of work.

[aufdenkampe]

Let's plan on having a discussion sometime soon on this.

I understand the reasons why we don't want Units to be a CV within ODM2, and I think that was and still is a good decision, to allow ODM2 users to select any unit system they want. I'm not questioning that. This issue is about providing a unit system with SKOS and community moderation as an option for anyone to use, within ODM2 or elsewhere.

There are numerous reasons to host a full-featured Units CV on http://vocabulary.odm2.org. See our item 5 in our 2016-04-15 BiG-CZ/ODM2 Team Meeting Notes. At the time, we put off this task because we didn't have an immediate need, but we now do have that need. We also have targeted funding for it, and the WikiWatershed end-users have been begging for unit conversion for some time.

Here are the reasons we discussed on 2016-04-15:

• ODM2 Units table includes field for Units Link. We can’t currently populate this, because there is no URL/URI for each term.
• Want input from community
• Want adoption from the community
  • There is no other complete Units CV for Earth & Environmental data
  • We put countless hours in to merging the best of the best from all available units
  • This work could/should be published
• Want to expose the additional fields that we decided to share
  • These are listed in the “To Transfer to Online System” tab of the ODM2_UnitsTable-Combined-QUDT-CUAHSI Google Doc:
  • Extra fields:
  • Conversion Multiplier
  • Conversion Offset
  • Definition
• Foundation for any future discussion of developing a Variables / ParameterNames cross-walk

[aufdenkampe]

Connecting to https://github.com/ODM2/ODM2DataSharingPortal/issues/188 and https://github.com/ODM2/ODM2DataSharingPortal/issues/191.