Orca's visual chart interface uses standardised colours and symbols that closely mimic official paper charts
Viewing Chart Symbols on the app
To get more information about a chart feature whilst using the app, follow these steps:
Long-press the feature icon on the map
This will create a pinned location. Tap "View Info" in the menu that appears
This will display detailed information about the selected feature. See the example below:
Chart Colours, Markers & Symbols
Below is an overview of the different symbols you can find in the app:
Colours
Grey – Land: Do not sail here
Blue –
When zoomed in: blue indicates shallow waters. Affected by your Depth Threshold setting
When zoomed out: All water is blue, with darker shades indicating deeper waters
White -
When zoomed in, it represents deeper waters
Does not appear when the map is zoomed out
Green – Intertidal Zones: Dry at low tide, submerged at high tide
Magenta – Warnings, Notices, Restrictions
Buoy colours
IALA A areas: applies to most of the world
Red – Port-hand: Keep to your left when entering from sea
Green – Starboard-hand: Keep to your right when entering from sea
IALA B areas: North & South America, Japan, Korea and the Philippines
Red – Starboard-hand: Keep to your right when entering from sea
Green – Port-hand: Keep to your left when entering from sea
Symbols
Anchorage – Safe place to anchor and where it would be unsafe to do so
Ferry Lanes / Traffic Zones – Areas with vessel traffic separation, sailing vessels must avoid these as much as possible
Rock / Submerged Danger / Wrecks – Exercise caution
Anchor (safe place) | 
Prohibited anchorage point | 
Sector center | 
Ferry |
Traffic Separation Arrow | 
Rock | 
Rock Awash | 
Rock Submerged |
Wreck: Non-dangerous | 
Wreck: Dangerous
| 
Wreck Mast |
|
Beacons & Buoys
Cardinal (N, E, S, W) – Mark dangers and indicate safe water direction
Lateral (Port, Starboard, Channel) – Show navigational routes and limits
Safe Water & Isolated Danger – Special buoys for open water or hazards
Shapes: (Can, Cone, Sphere, Spar, Pillar) – Indicate buoy type and meaning
Beacons
Cardinal North | 
Cardinal South | 
Cardinal East | 
Cardinal West |
|
Square | 
Pyramid | 
General | 
Round |
|
Danger | 
Mooring | 
Beacon | 
Beacon Cardinal North |
|
Beacon Cardinal South | 
Beacon Cardinal East | 
Beacon Cardinal West
| 
Beacon Lateral Starboard |
|
Beacon Lateral Port
| 
Beacon Lateral Channel Port | 
Beacon Lateral Channel Starboard | 
Beacon Lateral Port iala b |
|
Beacon Lateral Starboard iala b | 
Beacon Lateral Channel Port iala b | 
Beacon Lateral Channel Starboard iala b | 
Beacon- General Tower (yellow) |
|
Beacon-General Pole (yellow)
| 
Beacon- Safe Water Area | 
Beacon- Isolated Danger |
|
|
Buoys
Buoy Pillar | 
Buoy Pillar- Cardinal North | 
Buoy Pillar- Cardinal South | 
Buoy Pillar- Cardinal East |
|
Buoy Pillar- Cardinal West | 
Buoy Pillar- Lateral Port | 
Buoy Pillar- Lateral Starboard | 
Buoy Pillar- Lateral Channel Port |
|
Buoy Pillar-Lateral Channel Starboard | 
Buoy Pillar- Lateral Port iala b | 
Buoy Pillar- Lateral Starboard iala b | 
Buoy Pillar- Lateral Channel Port iala b |
|
Buoy Pillar- Lateral Channel Starboard iala b | 
Buoy Pillar- Safe Water Area | 
Buoy Pillar- Isolated Danger | 
Buoy Spar |
|
Buoy Spar- Cardinal North | 
Buoy Spar- Cardinal South | 
Buoy Spar- Cardinal East | 
Buoy Spar- Cardinal West |
|
Buoy Spar- Lateral Port | 
Buoy Spar-Lateral Starboard | 
Buoy Spar- Lateral Channel Port | 
Buoy Spar- Lateral Channel Starboard |
|
Buoy Spar- Lateral Port iala b | 
Buoy Spar- Lateral Starboard iala b | 
Buoy Spar- Lateral Channel Port iala b | 
Buoy Spar- Lateral Channel Starboard iala B |
|
Buoy Spar- Isolated Danger | 
Buoy | 
Buoy- Lateral Port | 
Buoy- Lateral Starboard |
|
Buoy-Lateral Channel Starboard
| 
Buoy- Lateral Port iala b | 
Buoy- Lateral Starboard iala b | 
Buoy- Lateral Channel Port iala b |
|
Buoy- Lateral Channel Starboard iala b | 
Buoy- Safe Water Area | 
Buoy- Isolated Danger | 
Buoy- Can |
|
Buoy- Sphere | 
Buoy- Cone |
|
|
|
Structures
Towers, Pylons, Cairns, Poles – Man-made aids to navigation
Dolphins, Piles, Mooring Buoys – Indicate mooring or hazard structures
Tower | 
Pylon | 
Cairn | 
Pole | 
Mooring Facility Dolphin | 
Mooring Facility Pile | 
Mooring Facility Buoy |
Special Features
Seaplane Areas, Marine Farms, Wind Turbines – Marked for safety and avoidance
Fog Signals, Floodlights, Vertical Clearance Warnings – Alerts users to key risks or limits
Fog Signal |
 Sea Plane | 
Weed Kelp | 
Wind Motor |
Marine Culture | 
Floodlight | 
Vertical Clearance Warning | 
Vertical Clearance Pass |
Unsurveyed Areas
Unsurveyed areas within zones where we otherwise have chart coverage are shown with blue and white stripes (see below)
