Reference

Every surface,
in the app's own words.

NavView calls a route a route and a run of it a passage; a drawer is a drawer and an instrument card is a face. This page uses those names, so what you read here is what you will see on the screen.

Charts Store Instruments Routes Marks Tracks Anchor MOB AIS Weather Fix quality Connections Diagnostics Tools Chart options Vessel Help Platform

01 · Charts

The chart engine

A native C and C++ engine rendering with OpenGL ES, carrying a port of OpenCPN's s52plib presentation library. Cells are compiled to a private SENC cache keyed on path, modification time and size, so the second open is fast.

Formats read7

S-57 · ENC

Official vector cells, rendered to S-52

Full symbology: point symbols in paper or simplified style, plain or symbolised area boundaries, four-shade or two-shade depth colouring, light sectors, and chart text with national-language and de-clutter options.

OSENC · .dec

Decrypted OSENC cells

Accepted through folder, ZIP or single-file import.

.nav packs

Encrypted chart packs, locked to NavView

Public header plus AES-256-GCM around validated cell data. Catalogued without decrypting, opened once on first use, and failing closed if tampered with.

BSB · KAP

Raster charts, baked on import

Converted to a tile set and fit file, then drawn through a warped-raster mesh.

GeoTIFF

Any CRS that PROJ can invert

Baked to the same tiles-and-fit pair as KAP.

MBTiles

Raster tile archives

With a configurable parent-zoom fallback depth, matching OpenCPN's behaviour.

PMTiles · MVT

Vector tile archives

Archive reader, Mapbox Vector Tile decoder, rasteriser and style. OpenCPN has no equivalent.

Quilt, basemap and text

QuiltingReference-chart picking, territory clipping and LRU eviction across cell boundaries.
World basemapA baked vector blob shipped with the app: OpenStreetMap land polygons to harbour zoom, Natural Earth bathymetry bands, GSHHG lineage, and a GeoNames plus GEBCO undersea-name gazetteer. It fills anywhere no chart cell covers, and can be switched off.
Scale minimumSCAMIN handling, plus an additional cull for cells whose SCAMIN is missing or weak.
Magnetic variationA real World Magnetic Model, with bearings displayed true, magnetic, or both.

Chart palettes The same harbour in Day, Dusk, Night, Dark and Paper Slot 04 · phone portrait

Slot 04 — chart palettes

02 · Charts hub

Library, Store, My Charts

Three tabs. What you already have, what you can add, and what you brought yourself.

Library

Packs on the device

Browse a whole set on a coverage map, with a band strip, sort cycle, and search by title, cell name or state.

Store

67 packs across four regions

Americas, Europe, Mediterranean and Atlantic Isles, Africa and Indo-Pacific. Each pack shows its coverage polygon, edition, cell count, download size and price. Filter by all, available, free, or already in your library.

Get · Buy · Update

My Charts

Everything you imported

Activate, show or hide, and delete, per row.

Import

Folder, ZIP or single file

An o-charts folder or chart-set directory copies in the background and survives leaving the app. A ZIP of cells becomes one set. A single .dec, .nav, .kap, .tif, .mbtiles or .pmtiles comes straight in.

Pricing

One-time purchases, tied to Google Play

US waters — NOAA ENC — are free. Regional packs are one-time buys with a reduced upgrade price if you already own a previous edition. Once a pack is on the device it works with no signal and no online open check.

Chart store The Store tab with coverage polygons and pack rows Slot 05 · phone portrait

Slot 05 — chart store

03 · Instruments

Dashboard, pills and floating gauges

Data appears in three places: a swipeable pill pager over the chart, a three-page dashboard, and gauges you pin wherever you want them.

Dashboard The Navigation page, with floating compass and depth gauges pinned over the chart Slot 06 · phone portrait

Slot 06 — dashboard and floating gauges

Top pill pager

The active context, over the chart

Swipe between MOB, anchor, route, track, AIS, GRIB and instrument pages. Priority is automatic — a man-overboard or a dragging anchor takes the front.

Status bar

Position, SOG, COG and scale

With a labelled scale bar showing both ground distance and the ratio.

Navigation page

SOG · waypoint name and number · ETA · DTW · BTW · COG · depth · VMG to waypoint · XTE with port or starboard of track · barometric pressure · air and water temperature.

Sailing page

TWS · AWS · VMG · VMG to waypoint · tack heading · depth · SOG.

Motor page

RPM · SOG · pitch, with fuel rate and engine hours arriving over NMEA 2000.

Floating gauges

Compass, wind, depth and speed

Pin them from the dashboard, then long-press to move, resize between three sizes, swap the type, or unpin.

Chart orientation

North-up, head-up, course-up

Tap the compass to cycle. Head-up falls back to COG when there is no heading source.

04 · Routes

Routes and passages

A route is the object you build. A passage is the run of it. Long-press the chart, choose Route, and every tap adds a leg.

Passage face

Distance remaining, ETA, TTG, leg breakdown

The hero card of the route drawer, with the whole passage folded into one readout.

Offline bar

A course deviation indicator

Off-track distance against a configurable half-scale, with your own yellow and red thresholds. Offline here means off the track line, in the nautical sense.

XTE corridor

Dashed rails on the chart

Port green and starboard red with a soft fill, plus leg range-and-bearing cards, waypoint labels and animated route flow.

Geometry

Rhumb line or great circle, per route

With route colour, line style, width, description and a planned departure time.

Arrival

Advance on arrival only

Never by passing abeam. Default arrival radius, or a radius and planned speed per waypoint.

Send to GPS

Waypoint and route sentences to a chosen sink

Emitted in the exact form OpenCPN uses, including the doubled waypoint sentence that keeps Garmin units happy.

GPX

Import, export and share

Single route, all routes, or a multi-selection. NavView also registers as an opener for GPX files elsewhere on the device.

Edit verbs

Reverse · Duplicate · Renumber · Show on chart · Route from track · Convert measurement to route

Passage face An active route with the passage face and the XTE corridor on the chart Slot 07 · phone portrait

Slot 07 — active passage

05 · Marks

Waypoints and marks

A mark inside a route is a waypoint; standing on its own it is a mark. Drop one with a long-press, from the floating tool, or at the vessel.

Waypoint manager The mark ledger in select mode, with the icon picker open Slot 08 · phone portrait

Slot 08 — waypoint manager

Icons

329 markicons in twelve categories

General, aids to navigation, hazards, services, activities, authorities, information, landmarks, sea and currents, weather, symbols and system — with a searchable picker.

Mark info

Folds for everything you might set

Identity, position in degrees and decimal minutes, display, scale minimum, arrival radius, range rings, links, and metadata.

Verbs

Go to · Route from · Insert after · Remove from route

Filters

Five ways to narrow the ledger

Visibility, route membership, icon type, distance from the vessel, and date added.

Lock waypoints

A setting that stops marks being dragged on the chart by accident.

06 · Tracks

Track recording

Tracks are never automatic. You start them, and stopping takes two taps — arm, then confirm — so a sleeve never ends a log.

Recorder

A faithful port of OpenCPN's commit algorithm

Cross-track-driven point commits, three-point collinear elimination, and minimum distance and time guards — so a log follows the shape of what you did without hoarding points.

Runs in the background

A foreground service keeps logging with the screen off, declared for continuous track logging from external position sources.

Precision

Low, medium or high

With a GPS jump filter, and daily rotation at a time you choose in UTC, local mean time, or device time.

Track info

A live stage while recording, a face when done

Distance, duration, maximum SOG and point count in stat wells, plus the points table, appearance and rename.

Reduce data

Douglas–Peucker simplification, off the main thread

For when a week of coastal hopping has become more points than you need.

Export GPX · Share GPX · Create route from track · Extend · Merge · Bulk show and hide

07 · Anchor watch

Two watches, two modes

Watch 1 and Watch 2 are independent, each with its own ring on the chart, labelled W1 and W2.

Drift mode

Alarm outside

You set a swing fence, and the watch alarms if you leave it. Seed it from your own ship, or long-press where the anchor actually went down.

Keep-out mode

Alarm inside

The inverse — a ring you want to stay out of, such as a rock or a neighbour's swinging circle. Stored as a signed radius, so you never type a negative number.

Loss of fix

Treated as an alarm, on every armed watch

If there is no valid fix for the stale window while armed, all active watches alarm — not only the first.

Alerting

Visual always, vibration on by default, an optional alarm sound, and a five-minute snooze per watch.

Readouts

Distance · radius · bearing · max · drift rate · mode · alert · status · margin · fence

Over a polar swing plot carrying a 300-sample trail, with an anchor pill on the chart showing distance, radius, bearing, SOG, time and depth.

Watch 2 Dragging

Keep-out · alarm inside · 212°T from mark

18.2m inside 25 m ring

Max31.7m

Rate0.6kn

Margin—

08 · MOB

Man overboard

Held, not tapped, and deliberately not on the menu board — MOB lives on the chart's own rail so it cannot be reached by accident and cannot be lost in a drawer.

With a fixA mark is placed at your position the moment it fires.
Without a fixIt arms and waits, then drops the mark on the next valid position rather than guessing.
Guidance faceReturn bearing and range, with a persistent high-priority notification from its own foreground service.

MOB The man-overboard guidance face with return bearing and range Slot 09 · phone portrait

Slot 09 — MOB guidance

09 · AIS

Traffic

Class A and B targets, aids to navigation, and static and voyage data — over NMEA 0183 VDM and VDO sentences, or seven NMEA 2000 PGNs.

AIS traffic The traffic list with Threat and Clear sections, over targets on the chart Slot 10 · phone portrait

Slot 10 — AIS traffic list

Traffic list

Threat, then Clear

Header counts read danger, near and active. The Clear section collapses. Recenter pans to the nearest or highest-threat target.

Risk tiers

Danger · Near · Clear

Worked from CPA and TCPA against your thresholds, and failing closed — if the engine cannot trust a CPA, it does not pretend to.

On the chart

True vessel size at close zoom

COG arrows with configurable length, target tracks, names above a scale threshold, distant-target attenuation, and a cross-out on lost targets before they are removed.

Suppression

Suppress alerts beyond a range, and for moored or anchored targets below a speed threshold, so a marina does not light up the screen.

Honest limit

CPA alerting is visual

There is no dedicated CPA alarm sound, and CPA is deliberately kept out of the notifications inbox. It is decision support, not a guard.

10 · Weather

The forecast

GRIB answers what is the weather going to do this week.

GRIB overlay

Forecast

GRIB1 and GRIB2, gzip or bzip2, decoded on the device. Twelve parameters — wind, air temperature, CAPE, pressure, precipitation, cloud, sea temperature, wave height, reflectivity, humidity, gust and current.

Six render layers stack additively: colour field, barbs, isobars, arrows, numbers and particles. Eleven colour schemes, per-parameter units, isobar interval and labels, arrow form and spacing.

Multi-step files get a transport bar for playback. A bundled source browser fetches from ECMWF Open Data, NOAA GFS, WaveWatch III and RTOFS, prefilled for the view you are looking at — and NavView registers as an opener for GRIB files arriving any other way.

GRIB overlay A wind field with barbs and isobars over the chart, with the transport bar Slot 11 · phone landscape or tablet

Slot 11 — GRIB overlay

11 · Fix quality

GNSS as an instrument

Navigation card

Mode · satellites · SNR · HDOP · VDOP · PDOP · age · differential age · figure of merit

Quality trend

A 300-second rolling window with CEP

So a degrading fix is visible as a trend, not a surprise.

Satellite signal

Per-satellite bars, locked and visible counts

Constellation chips, multi-band detection, and a satellite launch-year catalogue.

Sky plot

Elevation and azimuth, referenced to true north

A ring marks the satellites actually used in the fix.

Interference watch

RF interference and possible spoofing

Plus obstruction detection by azimuth slice, which tells you where the problem is rather than only that there is one.

12 · Connections

Inputs, router, outputs

77 NMEA 0183 sentence types are decoded across nine categories — GPS, AIS, instrument, autopilot, waypoint, radar, environmental, communications and system.

NMEA 2000Early access

Gateways

Actisense NGT-1 over USB, Yacht Devices over UDP

Plus file replay for testing. Fast-packet reassembly with a canboat-derived PGN dictionary.

PGN filter

Position · motion · heading · depth · wind · speed through water · environment · AIS

Source preference

Prefer N2K, or prefer 0183

A global tie-break when the same quantity arrives on both buses. A source arbiter handles competing 0183 GPS sources with a source lock.

Honest limit

NMEA 2000 is labelled early access in the app: validated against synthetic fixtures, with limited hardware soak. NavView listens on the bus and does not write to it.

Connections The Connections drawer with input cards and the router's forwarding categories Slot 12 · phone portrait

Slot 12 — connections drawer

13 · Diagnostics

Technician tools, in the box

Normally this is a separate paid app. In NavView it is three hub tiles and a status page.

Terminal

The raw 0183 tape, coloured by sentence type, with source filter pills, freeze and resume, split view, and controls for buffer size, font size and line spacing.

Decode

The same stream, decoded and grouped by category, with a per-field breakdown, a freshness pulse, and a written explanation of every one of the 77 sentence types.

NMEA 2000

An isolated, listen-only bus analyser: device inventory with product info and live PGN values, plus a raw frame terminal with filtering, errors-only and hex. It never writes to the bus or the navigation feed.

Status

One glance at system health

GPS, charts, NMEA sources, data rate and AIS, each reading OK, warn or fail. AIS appears only once the app has actually seen a VDM or VDO sentence.

Notifications

An inbox with severity and acknowledgement

Chart engine messages, an empty chart catalogue, man overboard, loss of GPS fix and anchor events. AIS CPA is deliberately excluded.

14 · Touch tools

Long-press the chart

One gesture opens six tools: WPT, Anchor, Route, Query, Climate and Measure. One-finger pan, pinch to zoom, double-tap to zoom, two fingers to rotate, and a short tap to select a feature.

Object query

Tap any chart feature and read it properly

Stacked objects listed, S-57 attributes decoded into plain language, INFORM and NINFOM prose segmented, TXTDSC note files opened, and light sectors given their real geometry — sector bearings, nominal range, colour and leading-light flag.

Curated for lights · buoys · beacons · depth areas · wrecks · obstructions · bridges · cables · TSS · anchorages

Measure

Range and bearing, multi-leg

Totals and per-leg readouts, TTG and ETA, point count, start-at-the-vessel, undo, clear — and convert the whole thing into a route when it turns out you meant it.

Climate

A point climate summary for wherever you pressed.

Object query A queried light with its sector geometry and decoded S-57 attributes Slot 13 · phone portrait

Slot 13 — object query

15 · Chart options

What the chart shows

View

Orientation north-up, course-up or head-up, and look ahead.

Vector charts

ENC on or off, display category, spot soundings, chart information objects, chart outlines, aid-to-navigation names, light descriptions, and the mariner selectors for accuracy and ZOC hatching and full light lines.

Text

Chart text, national text, important text only, and de-cluttered text.

Symbology

Point symbols paper or simplified; area boundaries plain or symbolised.

Depths

Four-shade or two-shade, with your own shallow, safety and deep contour values in your depth unit.

Labels

Halo, hide overlapping, and themed label colours.

Basemap

On or off, plus the MBTiles fallback depth.

16 · My vessel

Your boat, drawn to scale

Multiple vessel profiles — switch, duplicate, rename or delete — each carrying the particulars the plotter needs to draw you correctly.

True size own shipLength overall, beam and GPS offsets from bow and midship produce a parametric hull, so at close zoom the symbol is your boat rather than a generic arrow.
AppearanceHull colour and outline, bow sharpness, transom width, cabin scale and shift, minimum screen size and scale factor.
Predictors and ringsCOG and heading predictor lengths, and range rings with mode, distance, units and colour.
Honest limitDraft is stored for reference. It does not set your safety contour and it does not arm an alarm.

My vessel The vessel profile with the parametric hull preview Slot 14 · phone portrait

Slot 14 — vessel profile

17 · Help & settings

A manual that ships with the app

Guide

39 topics across 14 categories

Bundled, so it works with no signal. A home board, an outline drawer, title search, section jump chips, and a back-and-next spine that walks every topic in order.

Units

Distance · speed · depth · wind speed · height · temperature · pressure · bearings

Nautical miles, kilometres or statute miles. Metres, feet or fathoms. True, magnetic, or both.

Display

Chart palette, object and text scale, UI scale, full screen, raster detail, auto-follow, look ahead, smooth zoom, pan fling, zoom to touch point, an FPS overlay, and a low power mode that caps the frame rate.

Interface

Show the status bar, chart bar and compass window, toolbar auto-hide and its timeout, and the anchor alarm sound.

Alarms

There is no single alarms page, and the app says so

Anchor sound sits under Interface, CPA thresholds under AIS, radii on the anchor drawer itself. There is no depth sounder alarm at all — depth is visual.

Menu hub The hub board and mono dock on a tablet in landscape Slot 15 · tablet landscape

Slot 15 — menu hub, tablet

18 · Platform

The facts

Android	8.0 Oreo or later
Architecture	64-bit ARM (arm64-v8a)
Form factor	Phone and tablet, portrait and landscape, with layouts that re-rhythm rather than restructure
Rendering	OpenGL ES, hardware accelerated, with a low power mode
Chart formats	S-57 · OSENC · .nav · BSB/KAP · GeoTIFF · MBTiles · PMTiles
NMEA 0183	77 sentence types across nine categories
NMEA 2000	Actisense NGT-1 and Yacht Devices gateways · early access · listen-only
Position sources	Device GNSS · Bluetooth SPP · BLE · USB serial · TCP · UDP · simulator
Works with no signal	Charts, basemap, symbology, icons and the manual are all on the device
Accounts	None. No login, no cloud, no user database
Analytics	None compiled in
Price	Free, every feature unlocked. Chart packs are one-time purchases; US waters are free
Credits	OpenCPN and s52plib · OpenStreetMap (ODbL) · Natural Earth · GSHHG · GEBCO · GeoNames (CC BY 4.0) · OpenMoji (CC BY-SA 4.0)

Not a primary means of navigation

NavView is a companion for planning and situational awareness. Always navigate with official charts and approved equipment, and cross-check anything the app tells you against an authoritative source before you rely on it.

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