Interface TrackProperties

Number of points returned across all segments.

Which of the requested TracksRequest.properties the provider actually returned.

Reported rather than inferred, for the same reason resolution and epsilon are: a client must be able to tell "this provider does not have that path" from "that path had no values in this window".

Bounding box of the returned geometry, [west, south, east, north].

The Signal K context this track belongs to, when it has one.

Absent for an imported track that names no vessel — a GPX a friend sent, with no MMSI in it. Such a track is still a track: a recorded series of positions, which is what this API serves. What it is not is a claim about a vessel in the data model, so it carries no context rather than an invented one.

Name of the vessel, aircraft or other context, when known.

Not the name of the track — see name for that. A track recorded from position data has no name of its own; an imported one usually does.

Recording time of every point, ISO 8601 UTC, nested to match geometry.coordinates: coordTimes[i][j] is when coordinates[i][j] was recorded.

Follows the coordTimes convention used by GPX-to-GeoJSON converters, which RFC 7946 permits as a foreign member of properties. The nesting for MultiLineString is specified here because the convention only covers LineString.

Simplification tolerance actually applied, in metres.

Time of the first returned point.

Absent for a track whose points carry no times — an imported GPX without <time> is a shape someone sailed, with no recording times to report. Present for everything a provider recorded itself.

Identifies this track within the provider that holds it.

Stable for as long as the track exists. A provider mints it and receives it back unchanged in getTrack and deleteTrack; the server prefixes its registry name to form the providerId:trackId a client addresses, so a provider never has to know what it is registered as.

A recorded track may derive it from the context; an imported one has nothing to derive it from and gets an opaque id.

Optional because not every provider identifies tracks as objects. One serving a time-and-context query out of history has no handle to mint and implements neither getTrack nor deleteTrack; requiring an id there would mean inventing one that addresses nothing.

When a client added this track with TrackApi.storeTrack (POST /tracks), as an ISO 8601 time. Absent on a track the provider recorded itself.

Set by the provider; a value in a posted track is ignored.

Whether this is the own vessel's track.

Absent along with context: a track that names no vessel cannot be the own vessel's, and saying false would imply the question was asked of a vessel that exists.

The track's own name, when it has one.

A GPX <trk><name> survives an import here. Recorded tracks have no name until someone gives them one, which is why this is separate from contextName rather than overloading it.

Which registered provider answered for this track.

Set by the server from the registry, so a provider neither has to name itself nor can name itself wrongly. Every registered provider is queried and their features concatenated, so a vessel recorded by two of them yields two features, and this is what tells them apart.

Spacing actually applied, as an ISO 8601 duration.

Time of the last returned point, absent whenever from is.

Values for each requested path, keyed by path and nested to match coordinates: values[path][i][j] belongs with coordinates[i][j].

A position with no value for a path at that instant carries null rather than being omitted, so the arrays stay aligned.