Offline use ability

  • Sailor

    Hi, just a question. How do you imagine "offline use ability"?

  • Administrator

    @idefix37 That is an excelent question :-) Even we do not know what would be the best solution. Should we just keep the last displayed data, so you can see without an internet connection what you saw last "online time"? Or should we allowed to download forecast for selected region, so you can watch the weather of selected area without internet connection (similar to Google Maps offline mode). Or would be exporting of detail/meteogram to eg PDF enought? And what about mariners, pilots, drivers, ... what they are need and want offline?

  • Sailor

    I can only speak about sailor needs. When being at sea and offline, how to get numerical weather forecasts? (I'm not talking about VHF/HF Marine Radio voice services or radiofax weather maps via HF SSB radio).
    For me there are 2 cases: either you do transoceanic voyages which will last more than a week without landing, or you make short passages while being offline for 4 or 5 days maximum.

    • Long offshore voyages (one week or more): Numerical weather maps are obtained at sea by satellite receiver which can be a simple satellite phone. However this type of device can only receive light files such as e-mail or weather files in GRIB format. Then these files require a viewer software to get wind or wave field maps ... I understood that Windy is not allowed to send GRIB files because of a licensing issue (at least for ECMWF files). So it seems impossible for Windy to meet the needs of these long route sailors.

    • Short offshore passages (4 to 6 days max.): In this case we download on a laptop GRIB files (generally these are GFS files) for the week ahead and we use this forecast during the voyage. Of course the reliability of the forecast decreases when the length of the trip increases. If we plan a stopover every 4 or 5 days, this is acceptable, especially in summer. We just need to find a WiFi point on land to download a new forecast over several days. I think that more than 90% of sailors do such leisure sailing along the European or American coasts, in the Caribbean, etc...and there are very few of them crossing the oceans. As I often say « During a stopover, have a beer in a bar offering WiFi connection and download at same time recent weather data ». Currently to keep the Windy forecast in my iPad memory, on 10 days with a 3 hours step, I use the screen recorder feature while the time slider is scrolling.

    So the solution should be as simple as getting and using this type of video file. I don’t know if it is easy or not to offer this sort of solution on Windy. But it seems close to what you say « Should we just keep the last displayed data, so you can see without an internet connection what you saw last "online time"? »
    You should try to download iGrib to get an idea of what should be needed. IGrib is a very basic free app available only in the AppStore but it will probably give you some ideas.
    Exporting detail of Meteogram as pdf is not the solution for me because it just concerns a location, while a boat moves.

  • Moderator

    What about satellite internet?
    is not very expensive nowadays (31€/month)

  • Sailor

    Yes that’s not expensive, but probably using a fixed antenna, that you can install on a house but not on a boat. A boat is always in motion and need a special dome antenna. Given the cost of the equipment to get broadband connection to Internet at sea you must plan a good budget.

  • Moderator

    You're right!
    Boats have propellers!

  • Sailor

    Or sails (which have my preference) :-)

  • Banned

    This post is deleted!

  • Moderator


  • Sailor

    This message was just a spam hidden in the signature

  • I just want to second this request.

    If you can make the Windy app to downlowad GRIB compressed files, that would be very useful for sailors. Even a slow satellite or 3G connection would allow download. I am not aware of any licening issues with the GRIB format.

  • Sailor

    Please consider this announcement
    Data from ECMWF are not free and I understand that in the terms of agreement, Windy is only allowed to visualize these data but not to broadcast files of them, under GRIB format or any file format.

  • GRIB2 files are directly available on NWP providers repositories, e.g. here for GFS 0.25°.
    Of course, only for public, free of charge models.
    Be aware that the size of global models is not cheap: about 300 MB for each GRIB2 file (i.e. for each forecast validity, all grids)...

  • Actually it does not matter what format Windly would use (GRIB or not) - it can be anything that transfers data economically from their servers to the app. To keep the file small, one should be able to choose only a number of variables, say wind (at ground level), gusts, waves, swell, etc. for a particular region and a defined timeframe (2 to 5 days ahead). This is what TimeZero provides when donwloading weather files.

  • I don't know TimePack, but after a glimpse on their prices here , I understand better...

  • This is a really interesting problem. It sounds like people would gain enormous benefit just from GFS, and leaving ECMWF data to times when Wifi is plentiful. @vsinceac, just want to point out that full GFS files are indeed about 300MB, but you don't need most of the model fields – and NOAA lets you filter out smaller files with just the data you want.

    @idefix37 could I ask out of interest: do you tend to sail with a laptop, or just a cellular phone, or would you perhaps use special equipment inbuild on the boat to visualize these GRIB files? Because you could use GRIB software to your heart's content on a laptop, but trickier to deal with raw GRIB files on a phone!

    Really, the coolest solution would be for Windy to create a way to cache or save (in an offline Google Maps-type way) the maps on files on your device, and load them on request with the app. Then you could keep all the front-end javascript magic too... but I'm sure that's also the most difficult-to-implement solution :)

  • Sailor

    @johnckealy said in Offline use ability:

    It sounds like people would gain enormous benefit just from GFS

    You know there are already several app using GFS files at sea. But people could prefer to get these files and visualize them on Windy with the same features and friendly UI as they have online.

    Sailors using GRIB files at sea get them via internet if they are close to the coast or via sat phone if they have this equipment and are offline.
    In the first case you can imagine using a cellular phone, a tablet or a laptop.
    In the second case a tablet or mostly a laptop. Then it can be connected to the NMEA equipment on board.
    Personally I use an iPad at sea, but no satellite connection.

    @johnckealy said in Offline use ability:

    but trickier to deal with raw GRIB files on a phone!

    This is possible. Try it with Squid Mobile which is a good and free app, both on iOS and Android.

    With Squid Mobile when offline you can also receive GRIB files via Iridium Go.

    These screenshots are from my iPhone, with GFS data, in Irish Sea and close to Dublin.


    When max zooming with GFS 0.25° (15 NM), here is the distance between wind barbs on your screen.


    @johnckealy said in Offline use ability:

    Really, the coolest solution would be for Windy to create a way to cache or save (in an offline Google Maps-type way) the maps on files on your device,

    If I understand you, this is the solution I propose: keep in memory some layers on a limited area?

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