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Roadmap

The app draws charts. It does not yet know where the boat is. Below is the rest of what a chartplotter has to do, grouped into releases. The order is by dependency: each release needs the one above it.

No release here has a date.

0.1: Drawing the chart​

Shipped. Native S-101 datasets, S-57 cells converted into the same model, the official S-101 Portrayal Catalogue, a composed library, mariner settings, and a native shell on macOS, iPadOS, iOS, Windows, Linux and Android.

0.2: Reading the chart​

What the chart itself still owes a mariner. It comes before own ship, because the chart is the product.

  • Full pick report. The report lists the objects under the cursor and the cell each came from. The engine already returns every S-57 attribute, so the report should state them: light character, period, height and range; the depths of a depth area; the category and colour of a buoy. With the object names spelled out, not the six-letter acronyms.
  • Feature and place-name search. The search field goes to a position today. Names need an index in tile57 and a query in the C ABI.
  • The text and the pictures a cell points at. A feature can name a text file or a picture beside the cell, such as US348MDE.TXT, which usually carries a caution or a port description. The bake does not carry those files and the ABI cannot fetch them, so the report states the reference and marks it. Reading them means carrying them into the archive.
  • Outline the picked object. The report marks the point that was picked. To ring a point object where it stands, or trace the outline of a line or an area, the pick has to return the geometry. tile57_query_cb hands over the class, the attributes and the cell, so this is a change in the engine and in the C ABI before it is one in a shell.

0.3: Showing own ship​

The boat on the chart, and the numbers that come with it.

  • Position input. CoreLocation on Apple platforms, the Android location service, and NMEA 0183 over serial, USB, TCP and UDP.
  • NMEA 0183 parser in the core: RMC, GGA, VTG, GLL, HDT, HDG, HDM, DBT, DPT, VHW, MTW, MWV, MWD, ZDA.
  • Own-ship symbol with a heading line and a course-and-speed vector whose length is a time you choose.
  • Follow modes: centre on ship, and course-up.
  • Instruments: SOG, COG, HDG, depth, wind and water temperature, as a split view beside the chart and as a strip on a phone. Each value states when it goes stale.

0.4: Watching other traffic​

Other vessels, and the warnings that matter.

  • AIS from the same NMEA stream: VDM and VDO.
  • Targets drawn with the S-52 symbols, class A and class B, with heading, course vector, and the moored and lost states.
  • CPA and TCPA against own ship.
  • Target list, sorted by range or by closest approach.
  • Guard zone with an alarm.

0.5: Planning and recording a voyage​

Where you have been, and where you are going.

  • Track recording, drawing and GPX export.
  • Waypoints and routes on the chart, with GPX import and export.
  • Active route: bearing and range to the next mark, and cross-track error.
  • Alarms: anchor watch, depth, cross-track error and arrival, in one place, with a state that survives a restart.
  • Man overboard: one control drops a mark and starts a bearing and range to it.

0.6: Working tools​

  • Electronic bearing line and variable range marker.
  • Tides and currents from the harmonic stations in the cell.
  • Signal K as one network source for the boat.

Not scheduled​

  • S-63 encrypted commercial cells.
  • Radar overlay, where a platform gives a usable feed.
  • Weather (GRIB).

What the core needs first​

The chart scene is built one time and drawn with a uniform update per frame. That is why the app holds 60 fps, and it is also why own ship, AIS targets and tracks cannot live in that scene: they move every second, and a rebuild is far too expensive.

They need a second, small draw pass above the chart scene, with a vertex buffer the host updates per frame. The C ABI grows a few calls: set the own-ship state, give it a list of targets, append to a track. The work sits in the core, so every shell gets it at once and each shell only decides how it looks.

The NMEA parser belongs in the core for the same reason. The transports do not: a serial port on Linux, a Bluetooth link on iOS and a TCP socket on Android have nothing in common, so each shell opens its own and feeds sentences in.