GRIB Files for iPhones, iPads etc

What this page is about

Introduction

Since I first wrote this page, I have acquired an iPad and can comment with better knowledge on some of the apps that I know about. There will probably be others, especially on other platforms as the industry seeks to challenge Apple.

Of course, to use any of these handheld devices requires Internet access. Ashore and near the coast that is rarely a problem nowadays. Out at sea, it is clearly a problem. Olivier Bouyssou of Weather4D has pointed me to the Iridium AxcessPoint which creates a WiFi hotspot for connecting an Iridium to iPads and iPhone.

As with other GRIB services, the US GFS is the main source. I do not believe that it can be bettered significantly by any other available GRIBs. Put a different way, all these services give the same data, albeit with different presentations and options. Some services offer extra facilities. See my GRIB pages to learn what all this GRIB business is really about.

List of apps on this page

• iNavx[[
• Weathertrack
• iGrib
• Weather4D
• PocketGrib
• mobileGRIB
• Passageweather
• Other Apps

For convenience, and because I have an iPad, all images will be of that platform. Facilities using iPhones will be similar.

Click on images to enlarge.

iNavX

This is a Marine Navigation App for iPhone, iPod touch and iPad. Instructions can be found at iNavX site.

Displays look like -

The data are obtained via Saildocs with the email request being generated automatically. The reply will normally come back within one minute. You then click on the attachment to open in iNavX or any other GRIB app that you have. A good point about iNavX is that the chart projection is the same over the whole area of interest. I found the charts to be very clear and un-cluttered.

Weathertrack

Weathertrack is far more than just a GRIB app; It is nearly a one stop shop for marine forecasts. On the face of it, the displays seem rather fussy compared to the iNavX version, with a lot of processing for each picture. But, the same is so for all the apps. My preference would be for simpler presentations, but others may think differently. Chart projections are a little odd and charts become quite distorted in, say, the Baltic

Charts look like this

This seems to be the most advanced app to date (December 2011) with an update about to be launched. Users can determine the size of the area selected, grid point spacing, size of time step and number of days. They can choose a variety of models, including the Norwegian Met service HIRLAM (a European meso-scale model). Current strength and direction are available from the Bundesamt für Seeschifffahrt und Hydrographie. In the next version there will also be current predictions from the Norwegian service but only for the Skagerrak. There are weather actuals around the British Isles, updated hourly. There are wave models providing predictions in the enclosed waters of the Baltic and the Mediterranean as well as the open sea.

"Non-GRIB" products include synoptic charts from the UK Met Office and NOAA.

All in all, this is a useful app. At time of writing, the price was discounted £7.

iGrib

By contrast, iGrib produced by a Cruising Association member, is the simplest and most intuitive of the apps that I have looked at. I only had to refer to the manual to see how to delete a file. There are well chosen pre-defined areas with the ability to self select. There are the usual options of choice of number of days, grid spacing but not time intervals.

Winds, pressure, rain areas, cloud cover and temperature can be selected but not, a present, swell. There are no latitude/longitude grid and swell forecasts. Both will probably come later. There are no swell forecasts. There is no Meteogram facility.

Personally, I am quite happy to get swell predictions from the GMDSS forecasts but that is a very personal choice and others will think differently.

Displays of iGrib panels look like this

The cheapest app at £3. I am hoping to see a new version shortly (December 2011.)

Weather4D

Weather4D is a service with more general applications than just sailing. Some of the options are clearly designed for the general public rather than specialist use. There are GRIB wind and other parameters that are eye-catching. Unusually, they provide GRIB forecasts to 8 days ahead.

The overlay of winds and wave direction and height is vey clear. The area slection is the best, most flexible of all the apps in that the raio of north/south to east/west size is not fixed.

These are some samples -

Like other apps this has been developed since its introduction. Further changes will no doubt follow.

Current price is £4.

PocketGrib

PocketGrib, like other GRIB apps, is reasonably intuitive to set up and use. Users can choose map location, number of days, time intervals, grid spacing and data types required. The usual parameters of wind, pressure, rain, cloud cover. temperature and CAPE are all available. There are meteograms as well as charts with an offline capability.

These are examples -

I found it slightly clumsier than some of the others to use but has clear charts of wind and isobars. Less clear are sea state and the less important (to a sailor) parameters such as cloud cover and temperature. The charts of waves do not show height, only directions. You have to look at the meteograms with their none-too-clear scale.

I was not able to recall a GRIB for later viewing but that might have been my lack of familiarity with the app.

Current price is £4.

mobileGRIB

This is one of several weather Android apps for GFS and other marine weather information. Forecast times and parameters are pre-defined to pressure, wind arrows, temperature, cloud cover and precipitation for 5 days. This is to keep the download sizes small for low bandwidth regions.

This is, again, "work in progress." There are plans to allow -

• More GRIB parameters to select from
• Selection of parameters and forecast times
• Interpolation (ON/OFF)

These are examples -

Passageweather

Many will have used http://www.passageweather.com/ as an easy way to get vector wind charts from the GFS and other models. There is now a mobile version at http://www.passageweather.com/mobi

Area selection is from a list that mirrors the chart on the main site. Chart selection similarly. This is not just useable on an iPad or other device, it can also be used on a PC without all the advertising blurb. Good for those with restricted bandwidth.

Other Apps

There is a whole host of these, as might be expected. Mostly, these have presentations not particularly useful to sailors. Windfinder is one example. Go to for Android users for a collection of varied usefulness and take your pick. Try this for iPhones Apps. For iPad users try the AppGuide and the Weather App Showdown, both heavily US oriented. Or, simply go to the iTunes Store and look for weather forecasts.

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