Navigation: Navimetrix – a weather routing app with AI support and a vast range of features

Navimetrix was developed by the French developers Henri Laurent (known for SailGrib) and Olivier Bouyssou (known for Weather4D). The two have pooled their many years of experience and founded the joint venture SOFT4SAIL. The new app combines the best features of both its predecessors and significantly expands the range of functions. Unlike most of its competitors, Navimetrix automatically synchronises all routes, waypoints and settings via the cloud across all devices – regardless of the operating system.

A remarkable history of its origins

Navimetrix’s routing engine was originally developed for Virtual Regatta – a popular online sailing game with millions of users worldwide. More than 100,000 users accessed the routing service there every day. The developers used the game as a huge test bed for their software. If the infrastructure could cope with this load, it should also function without any problems with the significantly smaller number of real sailors. In practice, the app runs stably and very quickly on iOS and Android mobile devices, as well as on Mac and Windows versions.

Two-part system: routing and nautical charts separate

Navimetrix is clearly divided into two parts: the app itself handles all weather routing based on GRIB weather data, which must be downloaded separately. The nautical charts, however, are provided by the external supplier GeoGarage, which requires a separate subscription. For Germany, the nautical chart subscription with BSH data costs 25 euros per year; additional regions are charged for separately. The price list is not always transparent, however – for example, Denmark is shown as ‘not available’, but still worked in our app.

The nautical charts are raster maps from official providers such as the BSH for Germany. On screen, they look just like real paper charts. One drawback is that the transition between countries is not seamless. Even after downloading, you have to select the appropriate detailed chart for each sea area. Although the chart sets overlap – the Danish chart also covers German waters – the level of detail varies considerably. Harbour plans and fine details are only available on the respective national chart. This is considerably more cumbersome than with Navionics, Orca or C-Map, where everything works seamlessly.

For offline use, charts can be downloaded in full resolution (coastal areas) or reduced resolution (deep-sea passages) to save storage space and reduce data usage.

GRIB data: Easy to download, lots of models

Navimetrix’s real strength lies in weather routing. To do this, you first need to download GRIB weather data. The dialogue is relatively intuitive: select the sea area, specify the data type (atmospheric, tides, sea state, ensemble), and choose the resolution (global or regional high-resolution).

The range of models is particularly impressive. The free version only offers a basic GFS model with a maximum forecast period of five days. With premium access (Navimetrix subscription: 79.99 euros per year), you have access to six high-resolution regional weather models:

Arpège Europe 0.1° (11 kilometres)

• Regional model from Météo-France
• Coverage: Europe, including the Canary Islands
• Forecast: up to four days
• Ideal for: the English Channel, the Atlantic, the Mediterranean – reliably tracks large-scale European weather systems

Arome 0.025° (three kilometres)

• High-resolution model from Météo-France
• Forecast: up to 48 hours
• Ideal for: Coastal navigation in France – takes into account local effects such as sea breezes, summer thunderstorms and terrain-induced winds

Arome HD 0.01° (one kilometre)

• Highest-resolution version of the Arome model
• Forecast: up to 24 hours
• Ideal for: regatta sailing and inshore sailing – detects the slightest changes in wind near headlands, bays and coastal terrain. Please note: may sometimes react a little ‘nervously’

ICON Europe 0.07° (eight kilometres)

• Regional model of the German Weather Service (DWD)
• Forecast: up to five days
• Ideal for: the English Channel, the North Sea, the western Mediterranean and the adjacent Atlantic – considered the best model for the Mediterranean and a good complement to the French models

ICON D2 0.02° (two kilometres)

• High-resolution version of the ICON model
• Focus: Germany and neighbouring countries
• Forecast: up to 48 hours
• Ideal for: the North Sea and the Baltic Sea, where local factors (coastal winds, thunderstorms) are significant

UKV 0.05° (six kilometres)

• Regional model from the UK Met Office
• Coverage: the United Kingdom and neighbouring territories
• Forecast: up to 48 hours
• Ideal for: sailing around the British Isles, in the English Channel and in the Celtic Sea

A brief description of each model can be accessed directly within the app. You can customise the time step (e.g. hourly), the forecast period and the desired parameters (wind, air pressure, temperature, cloud cover, precipitation). The range of models available is therefore considerably more extensive than in most rival apps.

Routing: Professional and fast

Once the GRIB file has been downloaded, routing can begin. You need to create at least one start and one end waypoint. In theory, the app automatically calculates the entire route up to 15 days in advance. This works very well for long offshore legs. In confined waters, it has proved useful to specify a rough route with key waypoints – otherwise, the system may navigate over shoals or ignore bridge passages.

Routing requires boat data as a basis. Navimetrix offers a large database of polar diagrams; you can also upload your own polar data or use an integrated iPolar tool to create a simple polar diagram from just a few key data points. This isn’t as precise as a VPP-generated polar, but it’s better than nothing.

The routing function is not just intended for regatta sailors. You can set the system to engage the engine when the wind speed falls below a certain level (e.g. six knots) and specify the cruising speed at which to continue. For night-time sections, you can also reduce the polar power output or adjust the routing settings. One special feature is the option to ‘hold course’. This allows you to instruct the software to ride out short-term periods of strong wind that exceed the selected wind limit and to continue sailing once the front has passed. Conventional routing systems usually attempt to avoid strong winds under such conditions, resulting in significant detours.

Isochronous and interactive routing – like Expedition

A feature usually only found in professional route-planning programmes such as Expedition (over 1,000 euros): Navimetrix displays isochrones – lines representing equal travel times, which show all possible locations after, for example, an hour’s journey.

The big advantage is that you can simply move the cursor over the map and a route to that point is displayed straight away. If you click on the point, a new route from there is calculated in a matter of seconds. This is extremely handy if, whilst you’re out and about, you realise: ‘I actually want to go round to the other side of the island.’

Even more impressive: you can display various alternative routes side by side on the screen and watch the ‘little boats’ navigate them via animation. This makes it easy to see where you would be on each route at any given time, and which route is quicker in which section. Wind speed, boat speed and any need to use the engine are displayed along each route. A test route from Kiel to Oslo demonstrates just how fast the software works: the journey, which is around 300 nautical miles long, was calculated in just under eleven seconds. Orca takes around three times as long to perform the same calculation.

Zones of Interest – a brilliant workaround

The ‘Zones of Interest’ are a real unique selling point. You can simply click on the nautical chart with your mouse (or finger) to mark off-limits areas. The routing system then automatically avoids these areas. This is a perfect workaround when nautical chart data is incomplete and traffic separation schemes, wind farms or firing ranges haven’t been digitised in a way that allows the routing software to recognise them. With other programmes, this is a tiresome problem – Navimetrix solves it elegantly with just a few clicks.

AI sailing instructions

A brand-new feature not yet available in any other weather routing app: Navimetrix uses AI to generate an automatic briefing for every calculated route. You receive a detailed summary containing:

• Description of weather conditions
• Route
• Detailed risk analysis: What changes in the weather can be expected? Where are there risks of gusts? Are there any issues with tidal currents or headwinds? What are the sea conditions like?
• Recommendations on which additional weather charts to download

Routing Analysis and Statistics

Once routings have been created, they are saved and can be analysed in detail at a later date:

• Routes, distances and weather conditions for each section
• Statistics: Percentage breakdown by wind angle (e.g. ‘35 per cent close-hauled at 35° AWA, 20 per cent running at 150° AWA’)
• Input overview: Which weather model, time and polar were used?

This is particularly useful if you want to compare several routes with different parameters. A direct connection to the chartplotter is not possible; the routes must be exported as a GPX file and loaded manually onto the chartplotter.

AIS – extremely powerful

Navimetrix displays AIS data (from Internet AIS or your own on-board receiver) with heading vectors on the nautical chart. However, the app goes significantly further than other programmes: in a list view, AIS targets can be sorted using a wide range of filters:

• Distance, CPA (minimum approach), time to CPA
• Name, MMSI, Risk
• Time taken over ground (averaged over five minutes or 20 minutes)

There is also a free-text search box that allows you to search through the entire AIS stream. This also enables a reverse search, similar to MarineTraffic: search for a vessel’s name, click on it, and the map automatically zooms in on the target. Another feature: AIS targets can be grouped together (e.g. regatta participants) to display only these vessels and compare their speeds and courses.

Tides, live weather data, overlays

For tidal waters, it is not only the forecasts from GRIB data that can be used. In Germany, all BSH tide gauges are also directly accessible. Live weather stations on land (e.g. at airports), satellite measurements and ship-based measurements are also displayed on the nautical chart – clicking on a station shows the wind speed and air temperature.

The map backgrounds available include not only nautical charts, but also OpenStreetMap, Bing satellite imagery and real-time satellite data (weather). You can choose between global coverage or high-resolution regional images, allowing you to see live cloud cover. No other sat-nav app offers this feature yet.

The weather display is highly customisable: you can choose between average wind speed, gusts, gust difference, air pressure, temperature, precipitation, cloud cover, lightning and rain radar. The wind field can be displayed as traditional wind arrows or, as on Windy, as a modern particle animation.

​Cloud Sync – cross-platform

A major advantage is that all routing data is stored on the server. If you log in on a different device using the same account details, all routes, danger zones and settings are automatically available. This works across Android, iOS, macOS and Windows 11. Support for Linux and Windows on Arm is in the pipeline. We tested the software on an iPhone, iPad, MacBook and a Windows 11 computer.

iPhone and iPad: The app runs smoothly and reliably. On the iPhone, however, the screen is small, so fiddly tasks such as setting ‘Zones of Interest’ quickly become a bit of a faff (the ‘fat-finger’ problem). The iPad is a good compromise: the screen is big enough, performance is reliable, and the touch controls work well.

MacBook Air: There are pros and cons here. The big advantage is mouse control: intricate functions such as setting zones or detailed views are significantly more precise and convenient with the mouse. However, the integration with macOS is not yet optimal. Window management is unintuitive: whereas on the iPad a ‘Cancel’ button closes a dialogue box, on the Mac it opens a new window that you have to close separately – this feels like a freeze, but is simply a quirk of the interface.

Windows 11: The installation goes smoothly, and downloading the base data is quick and easy. The app runs smoothly and is very easy to use thanks to the mouse. The window management is actually slightly better than on a Mac, as pop-up windows are clearly identifiable as such. This reduces confusion when switching from a mobile device to the desktop or laptop version for the first time.

CONCLUSION

Navimetrix is an impressively powerful weather routing app with features usually only found in professional software costing over 1,000 euros. The isochrone display, interactive routing, AI sailing instructions and extremely detailed AIS integration are unique selling points. The cross-platform cloud synchronisation works very well.

The integration of nautical charts is a bit fiddly, as it does not work seamlessly across national borders and requires a separate GeoGarage subscription. The macOS version has stability issues, and the Windows version requires powerful hardware.

Navimetrix costs 79.99 euros per year; GeoGarage starts at 25 euros per region. This is significantly cheaper than professional software and comparable to other premium apps with much simpler routing. This makes Navimetrix appealing not only to regatta sailors who want to use professional weather routing without spending over 1,000 euros on Expedition, but also to ambitious cruising sailors.

Features and prices

• Platforms: Android, iOS, macOS, Windows 11 (Linux and Windows on ARM planned)
• Price: €79.99 per year (Premium with all weather models)
• Free version: Limited (only one weather model)
• Cloud Sync: when used with a Premium account
• Routing: Isochronous, interactive routing, weather routing
• AI sailing instructions: Yes (unique worldwide)
• GRIB models (Premium): Arpège, Arome (1 km), ICON Europe (8 km), ICON D2 (2 km)
• Forecast period: Up to 15 days, depending on the weather model
• AIS: Internet-based AIS or dedicated receiver, groups, filters, reverse search
• Display of NMEA data
• Polar database: Yes, wide selection + upload your own data + generator
• Engine routing: Yes (cruising in light winds)
• Night mode: Yes (reduced performance)
• Zones of Interest: Yes (restricted areas can be marked)
• Live weather data: airports, ships, BSH gauges
• Overlays: nautical charts, OpenStreetMap, Bing satellite imagery, weather satellite data

GeoGarage (nautical charts, separate subscription):

• Provider: External (not Navimetrix)
• Map type: Raster maps (official providers such as BSH)
• Price in Germany: €25 per year
• Offline download: Yes (full or reduced resolution)
• Seamless transitions: No (country-specific; manual change required)
• Level of detail: High only on the relevant country map (harbour charts, etc.)

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