1) The document discusses different ontologies that model observations and measurements, including PROV, SSNX, OBOE, BCO, and how their terminology and conceptualizations of key concepts like "observation" differ.
2) It presents observation as an activity according to PROV and argues that sampling and actuation should also be modeled as activities.
3) Aligning the ontologies and grounding them in upper ontologies like BFO can help address misunderstandings from different modeling approaches.