analyze topics usage

[tomkralidis]

At TT-WISMD 2025-04-15, the team discussed whether it is possible to perform further analysis of topic usage via the Global Replay service (i.e. how much use different topics are getting used).

I imagine we can derive this from a GRep (custom OGC API - Process) or GB, albeit with a short retention (so analysis of topics would only be as good as how far back a GRep (24 hours) or GB keeps messages).

IMHO this could be a "nice to have" (turning this into a wis2-grep RI enhancement issue), without it being defined in the guide per se. Thoughts? cc @golfvert @6a6d74

[golfvert]

This would be a typical Sensor Centre job.
We define a metric using (part of) the topic, starting at level 7 - earth domain discipline -, for example. Then for each message a +1 and done.
However, and as usual, it is not because we can create a metric, that we should.
What would be the use of those statistics?

[tomkralidis]

One use case is being able to access the amount of experimental topics to drive formalization of same (cc @amilan17).