Cursor-on-Target: the implemented event translation

A CoT event is a small XML document describing what, where, when and how sure. The type string encodes affiliation and battle dimension, the point element carries position with error estimates, and the detail element is an open container that implementations extend.

Its virtue is its size and its ubiquity. Its cost is that almost everything meaningful lives in convention rather than in the schema, so two conformant implementations can disagree about what a field means while both remaining valid.

That is why a published, field level mapping is worth more here than a claim of support. Anyone integrating can read exactly which conventions this implementation follows.

CoT is how a dismounted user's position, a sighting and a sketched control measure move between tactical clients today.

For a decision-support layer, being able to emit a plan as a drawing means a recommended course of action can appear on the same screen the user already has, without asking anyone to adopt a new client.

Reading atoms means the same layer can see the reported picture as the edge sees it, rather than as a headquarters system has already reconciled it.

Ingest takes one CoT atom, a contact report, and produces one Entity and one Event. The atom describes a thing that exists and a thing that happened, which is the same split every adapter in the set uses.

Egress takes one canonical object and produces one CoT event document. A plan object becomes a free-form drawing, and an Entity becomes an atom, which is what makes the ingest path round-trippable. Entity egress is not an extra: the harness calls the egress path on whatever ingest produced for every fixture, so an adapter that could only emit drawings would fail its own gate.

A drawing arriving on ingest is not special-cased. The CoT adapter does not produce a plan object from an incoming drawing; other adapters in release 3.3.0, such as GeoJSON and GeoPackage, do produce plan objects on ingest, so this is a CoT adapter choice rather than a rule of the data model. Such a payload is still translated, with affiliation and type resolving to unknown and its fields parked under the adapter's declared loss accounting.

The CoT sentinel for an unavailable height or error estimate is translated to an absent value rather than forwarded, because forwarding it would place a contact nine thousand kilometres up with nine thousand kilometres of error. The translation is declared, so it appears as a printed line in every harness report.

A position at zero latitude and zero longitude is not treated as a sentinel, because it is a real point in the Gulf of Guinea. An event with no point element yields no position; an event at zero and zero yields a position there.

An unrecognised how value resolves to estimated rather than to a satellite fix, because understating a fix is the safe direction when a commander is using that field to tell a measurement from a guess in a navigation-denied environment. The source's own value is kept either way.

XML parsing is guarded. A document carrying a document type definition is refused before the parser sees it, since a CoT event has no legitimate use for one and internal entity expansion is a memory amplification attack on bytes that arrive off a network.