Preview of pull request #35: Annotations, part B: draw and edit annotations on the map. Built from 1dc8db3 on 2026-10-13 13:07 UTC. All previews
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Try Debrief

This is Debrief v4 running in your browser: the same map, tool forms and results panel as the VS Code extension, and the same Python catalogue, history, tools and importers. Nothing is installed, and nothing you do or import leaves your browser.

Things to try

  • Select and run a tool. Click BLUE ONE in the outline, then Ctrl-click RED ONE. Closest approach is now on offer. Run it: the line appears on the map, the result opens beside it, and current time moves to the moment it found.
  • Look at a moment. Drag Current time at the top of the side column. Each track's position at that time is a square in its colour.
  • Narrow the time window. Drag either handle of Time window, or the band between them. The map shows the window as you drag: tracks are drawn in full within it and faintly outside it, and the tug's track, which ends at 10:35, loses its label once the window starts after that. Let go and the window is saved in the plot, but it's not a step in History, and Undo leaves it alone.
  • Play. Press ▶, or Space on any of the sliders. Choose a speed: at 60× a minute of the exercise passes each second. Playing stops at the end of the window.
  • A colleague changes the window. A colleague changes the time window, under Try, changes it as if from another computer: Debrief shows theirs and says so.
  • Add an annotation. Add annotation…, under the outline, opens a form for a line, area, circle, ellipse, label, marker or note. Type positions as you would write them (37°00.000'N 075°30.000'W), give a circle a radius and a colour, and press Add. Select it and press Change… to restyle it: each is one step in History. North arrow shows the chart's north arrow.
  • Draw on the map. Choose Area on the map's toolbar, click each corner and double-click the last; the map says ranges, bearings and the area as you go. Name it in the form and press Add. Select it and drag a corner, or Tab to a handle and use the arrow keys: each change is one step in History.
  • Read the narrative. The Timeline lists the plot's notes in time order. Choose one and current time moves to it.
  • Undo. Every change is a step in History. Undo replays the plot to the step before. Nothing is deleted: the undone step stays listed, and Redo brings it back.
  • Crash part-way through a save. This stops a save after the new plot file is written but before it replaces the old one, as a power cut would. Reopen the plot: it is exactly as it was before that save, and Debrief says a save was interrupted.
  • Add a plot file. Under Import your own, choose a Debrief plot file (.geojson), such as one a colleague sent you. Its whole history comes with it: undo, redo and going back to a step work on what they did.
  • Work alongside a colleague. A colleague changes the plot shows what happens when someone else saves a change: Debrief shows the latest and tells you. …while your next tool runs, then run a tool: Debrief asks whether to combine the changes or save yours as a new plot. It never overwrites theirs.
  • Import your own file. Choose a REP file or a legacy Debrief .dpf plot. It's read and imported in your browser, and everything that couldn't be imported is listed.

Measuring on the real Earth

Drag two positions and compare the range and bearing Debrief v4 measures with what legacy Debrief gave:

How it works

The page plays the part of VS Code. Debrief's webviews run unchanged in frames, and Debrief's Python packages run under Pyodide in a web worker, installed from the same wheels the desktop uses.

The sample exercise is copied into the browser's memory. Every change, undo and crash happens there, and is gone when you close the page.

The first start downloads Pyodide and its packages, about 16 MB, from the jsDelivr CDN (cdn.jsdelivr.net). Later visits use your browser's cache. If your network blocks the CDN, the map still works, and the page says that tools, history and import need Python.