Disturbances in the GRIB files

The disturbances are not only atmospheric, sometimes they are also in the transmission of GRIB files !

Some of you alert me for two or three days about difficulties to receive files, or the lack of data displayed in iNavX.

After checking in requesting last night from my iPad, force me to see, once a file loaded after long minutes of waiting, that the data were not displayed on the chart. By checking the GRIB display with MacENC, appeared only wind vectors, but not the contours. So I contacted by myself Richard Ray who, thanks to jet lag, was able to react immediately. Some discussion with Jim Corenman, director of GRIB files in Saildocs (*), allowed him to discover the source of the issue, à savoir une modification de la transcription des latitudes et longitudes :

I did make some recent changes to Saildocs' internal handling of latitude / longitude, pour m’accorder avec d’autres modèles (GRIB forecasts). There's no requirement that a grib be "normalized" to -180° (West) to 180 ° (East). Grib viewer needs to be able to display any format (including positive or negative dLat and dLon). That was also the problem I ran into with other models, so I am normalizing everything internally to 0 - 360 °, without negative longitude.

So Rich Ray has, his advice, re-work its files code for x-traverse server to handle all GRIB format, and has just informed me that it was now operational. This is the result, tonight at 9:00PM :

grib sur inavx

GRIB in iNavX iPhone and iPad

And the same file with MacENC :

GRIB dans MacENC

On the other hand, Jim Corenman said they had changed their server Saildocs on last wednesday, which explained the difficulties of access to files during the hours that followed the migration.

So everything comes in order, and we can applaud the responsiveness of Rich Ray to satisfy users of its applications !


(*) Saildocs.com is a leading online supplier of GRIB files from NOAA. Leur système de répondeur par mail permet d’obtenir des fichiers automatiquement depuis un logiciel (as iNavX) or email application.

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4 Replies to “Des perturbations dans les fichiers GRIB

  1. Yes, well just out of luck, that's when I was leaving for 1 000 nautical miles. So Ugrib and Mac Enc, the 1 000 miles that went well, a little wind anyway, Once the boat lying in the Windward Passage, but no big bad (cyclone), nor cold front. The season starts in November cold front in Cuba and winds can reach 60 knots (seems it), Suddenly I was wary of the still somewhat. See you soon, appointment at the Salon ? … nautical !!!

  2. Kudos to Francis for his availability, thank you developers for rapid response after the call Francis. I stayed still for more than three days without weather information. Fortunately I was warm on the ground ! This will not be the case next week; we can wonder about the current inability to load files elsewhere in case of trouble.

    PS: I'm not sure this is a problem of code iNavX, Indeed, the application is delivered to function without loading a new version. Par contre l’analyse des fichiers reçus montrait à l’évidence la présence de caractères « ésotériques » qui ont disparus dimanche matin.

    1. Not a code problem iNavX, but GRIB code translation before putting them on X-Traverse (il y a une « moulinette » intermédiaire).
      We can always upload it to his personal space X-Traverse another file GRIB format (.grb) they just have to ask since iNavX.

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