1 · Moving around the chart

• Pan — click and drag the map (one finger drag on a phone).
• Zoom — scroll the mouse wheel, use the + / − buttons, or pinch on a phone.
• Cursor position — the Cursor position box (top-right) always shows the latitude / longitude under your pointer, and a Scale bar showing the real distance in nautical miles.
• Position fix — click anywhere on the water and a card shows that exact spot in three formats (DD, DMM, DMS). Press Copy DMM to copy it.
• Go to position — type a coordinate such as 36.1, -5.3 into the Go to position search box at the top and the chart jumps there.
• Share a view — the web address updates as you pan and zoom, so you can bookmark it or copy the link and it reopens at the same spot. The chart also remembers which map layers you left switched on.
• Magnetic variation — the Variation line (top-right) shows the local angle between true north and magnetic north (e.g. 2.4°E), from the official World Magnetic Model. It's why bearings on this chart are shown as both °T (true) and °M (magnetic, what a compass reads).

2 · Map layers

The small layers panel lets you turn each map layer on or off. You can combine them freely — for example Ocean relief + Seamarks + Lat/long grid for a classic chart look.

Chart (OSM)

Standard OpenStreetMap base — roads, towns and coastlines. Good for finding ports and land detail.

Ocean relief

Bathymetric sea-floor base map (the default nautical look). Darker blue = deeper water.

Seamarks

Buoys, beacons, lighthouses and other aids to navigation from OpenSeaMap. Many lights blink like the real thing.

Depth (GEBCO)

Water-depth shading and soundings from the GEBCO global ocean grid (worldwide, but coarse — about a 450 m grid).

Depth HD (EMODnet)

Higher-resolution depth shading (about 115 m) from EMODnet — far more detail in harbours and approaches. Best coverage is European seas; elsewhere it may be blank, so use it together with GEBCO.

Lat/long grid

Draws the latitude / longitude graticule lines with labels along the edges.

Rain radar

Live precipitation radar — shows where it is raining right now, with recent frames.

Wind

Live wind overlay — direction and strength across the area.

Waves

Live sea-state overlay — significant wave height.

Day / night

Switches the chart between the bright daytime palette and the dim red-friendly night palette (same as the Night button at the top).

The weather layers (Rain, Wind, Waves) are live feeds, so they can take a moment to load and may be a few minutes behind real time.

3 · Planning & safety tools

Route

Click Route, then click points on the chart to lay down waypoints. The right-hand Passage plan lists each leg with its course in both °T and °M, plus the total distance and great-circle distance. Enter a Speed and it works out passage time and ETA. Clear removes the route, GPX exports it to a file, and Check scans the track for land and shallow water. You can also Save route under a name and reload it later from the drop-down (saved in this browser), with Delete to remove one.

Ruler

Range & bearing tool (an ECDIS EBL/VRM). Click Ruler, click a start point on the chart, then move the cursor — a line follows it showing the live bearing in both °T (true) and °M (magnetic) and the range (nautical miles, or cables under 1 nm). Click again to lock that measurement; click once more to start a new one. Turn it off with the Ruler button.

ARPA

Collision-avoidance. Set your own ship's course (COG) and speed (SOG); the panel lists nearby AIS vessels with their CPA (closest distance) and TCPA (time to it), and alarms when a ship will pass within 1 nm in the next 30 minutes. It also has an anti-grounding alarm: enter your draft and a safety margin and it warns when the charted depth under the ship drops below your safety contour.
Tip: click any vessel on the chart to see its own CPA / TCPA to your ship right in its info card.

VDR

Voyage Data Recorder — records your own-ship track as you move, which you can show on the chart, export as GPX, or clear.

Legend

Opens a key explaining every symbol on the chart — buoy colours, waypoints, own ship, AIS targets and the route line.

Night

Toggles the day / night chart palette (same as the layer above).

4 · Where the data comes from

• Ocean & relief base: Esri Ocean basemap (built from GEBCO, NOAA and National Geographic data).
• Seamarks: OpenSeaMap, built on OpenStreetMap.
• Depth: the GEBCO global bathymetry grid.
• Weather (rain, wind, waves): public live weather feeds.
• Ship traffic (AIS): the primary live feed is aisstream.io (free, worldwide). When it is down, the chart falls back to three open / free data sources, merged together:
  • Digitraffic — Finnish Transport Agency (Fintraffic) open data · the Baltic Sea.
  • Kystverket — Norwegian Coastal Administration "Kystdatahuset" open data · the North Sea, Norwegian Sea and Barents up to Svalbard.
  • VesselAPI — global coastal waters (Mediterranean, UK, the Americas, Asia and ports worldwide).

⚠ The live ship-traffic (AIS) feed is free and public, so it does not always work. It can drop out, lag behind, or only cover some regions. When the live feed is flowing you will see the green AIS LIVE badge; when it is down a backup open-data layer fills in, so the vessels you see may be partial or a little delayed.

⚠ This is a demo built on coarse public data — NOT FOR REAL NAVIGATION. Always use official charts and equipment at sea.