ssn: issue-139 strategy to connect sosa to ssn

I have just raised this issue in the tracker --- I am also emailing to the list as the automated email does not seem to work and this has got to be the number one issue going forward for SSN. I believe there are several options for resolving it, but it will not resolve itself without concerted effort and left unresolved we will have no SSN deliverable from the SDW.
-Kerry

Quote from charter
"The WG will work with the members of the former Semantic Sensor Network Incubator Group to develop its ontology into a formal Recommendation, noting the work to split the ontology into smaller sections to offer simplified access."


SOSA as it currently stands is completely disconnected from SSN. It includes
(a) terms that are also used in ssn but that have different meanings (both descriptively, formally and in application). e.g. sosa:Platform (issue-88<https://www.w3.org/2015/spatial/track/issues/88>),
sosa:Sensor (issue-93<https://www.w3.org/2015/spatial/track/issues/93>)
(b) terms for which there are very similar or identical SSN equivalents but different names e.g. sosa:resultTime ssn:observationResultTime
(c) terms that have no correspondence in SSN e.g. sosa:Sample

SOSA is not a simplified module of the most well-used (or most useful) parts of ssn which it should be. It is an independent (albeit simple) ontology. It has no formal nor semi-formal relationship to ssn -- being generous one could say perhaps that it is "inspired" by ssn. It has also lost connections to sensorML that are embodied in ssn.

There is no interoperability strategy nor tools, other than a weak human-readable(only) mapping table (currently WIP) that identifies some of the similar terms from each.  https://www.w3.org/2015/spatial/wiki/Mapping_Table

This fails to deliver on our charter. It only serves to confuse all our potential users.

There have been promises of an alignment ontology -- that could be helpful. But it would be very messy as sosa and ssn are currently defined. There was once an intention to import sosa into ssn -- that would be huge damage to ssn in the current state of sosa, importing a load of irrelevant and contradictory stuff for the sake of 3-5 useful terms? OTOH If sosa was instead a "core" of ssn this could be made to work well.

Please note that this is not an issue about those specific examples named here, as there are plenty more examples for each of these. It is an issue about a strategy to connect sosa to ssn and to deliver on our charter.

Maybe this is just a re-statement of old and still outstanding issue-48<https://www.w3.org/2015/spatial/track/issues/48>, issue-49<https://www.w3.org/2015/spatial/track/issues/49> and issue-37<https://www.w3.org/2015/spatial/track/issues/37> in the light of further development since then.