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 (chart scale below 100km/50 miles): Darker shades of blue indicate shallow waters. Affected by your Depth Threshold in chart settings
These colours change after each contour on the map
When zoomed out (chart scale greater than 100km/50 miles ): 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 |
Sail routing symbols
These symbols are used when hazards obstruct normal sailing during a sail route
 Route leg with depths potentially more shallow than routing settings |  Sail route leg that requires use of engine |
Unsurveyed Areas
Unsurveyed areas within zones where we otherwise have chart coverage are shown with blue and white stripes (see below)
