RTZ Route Exchange (.rtz)
RTZ Route Exchange (.rtz) is the XML route file ECDIS uses — the standardised way a ship's passage plan moves between electronic chart systems built by different makers.
At a glance
| Extension | .rtz |
| Encoding | xml |
| By | IEC / CIRM (Comité International Radio-Maritime) |
| Current version | RTZ 1.1 (XML namespace http://www.cirm.org/RTZ/1/1); 1.0 uses http://www.cirm.org/RTZ/1/0 |
History
RTZ answers the problem that a passage plan previously had to be re-keyed by hand whenever it moved between systems. IEC 61174, the standard for ECDIS equipment, defines the exchange format, and CIRM publishes the schema, which is why the namespaces are cirm.org URIs. Version 1.0 was followed by 1.1, which keeps the same document shape and changes the namespace.
Where it is used
RTZ is used on the bridge and ashore: planning a passage in one system and loading it into the ECDIS, moving a route between a shore office and a vessel, and handing a plan between vessels and systems of different makes. It is a working navigation format of commercial shipping rather than a consumer one.
Structure
An RTZ file is XML. A route element carries a routeInfo with the route name, a waypoints list and optionally schedules. Each waypoint has an id, a name, a position in decimal degrees and the geometry of the leg reaching it. A schedule is a separate list keyed back to waypoint ids holding an ETA per waypoint, in either a manual or a calculated branch, so positions and times live in different branches and are joined by waypoint id rather than by file order.
How widespread
Within commercial shipping RTZ is the interchange format for passage plans, because the ECDIS requirement drives it. Outside that world it is rare: most GPS formats grew out of consumer devices, this one out of a maritime equipment standard.
RouteConverter support
| Reads | RTZ Route Exchange |
| Writes | RTZ Route Exchange |
RouteConverter reads RTZ 1.0 and 1.1 and writes 1.0. Version 1.1 documents are accepted by rewriting the namespace while parsing, so one set of bindings covers both. Waypoint ETAs are read from the schedule branch and matched to waypoints by id, and a route without a name is given a default one because the schema requires it. Writing RTZ is free for the first ten saves; beyond that it needs the rtz-ecdis sponsor feature. Reading is always free and unlimited.
Specifications and documentation
- IEC 61174 — ECDIS operational and performance requirements
- CIRM — Comité International Radio-Maritime