What this page is about

UGrib is a service using FTP developed by a round-the-world racing sailor. It is well attuned to th needs of sailors. ZyGrib ia a very similar service and described on another page.


Introduction

Obtaining GRIB files using email services, as with SailDocs, or MailASail is efficient insofar as a great deal of information is contained in a small email attachment. This makes it suitable for use over mobile phones and, especially, using HF or HAM radio for email. The downside is that the user has to send an email to request the information. There are pitfalls in that the request email has to be exactly formatted. Another drawback is that it is necessary to go online and collect all emails that are in your mailbox.

There are two alternatives to using email. First, there is the browser approach. This is fine when ashore but can be prohibitively costly over a mobile phone and impossible via HF radio.

The second alternative, although not possible without an Internet connection, is to have a program that goes direct to the data source and downloads the data virtually immediately without the penalties of using a browser and all the attendant costs involved in accessing a webpage.

This is File Transfer Protocol, but do not worry about the name. It is a black box as far as we are concerned. This method is used by some commercial services, such as ProGRIB and Movingweather.

A free service, albeit with less data options at present, but great flexibility in operation has been developed by UGrib. This is one of the easiest of all systems to use.


Setting up and using

The starting point is to download the free combined data retrieval and viewer software from http://www.grib.us/. The download is about 2.5 mb, a little larger than with Saildocs but much less than other services. Having run the program you then have all the necessary software on your computer.

Area selection is on-screen and is extremely easy and precise (I found it rather more so than the commercial systems). It is extremely flexible in that users can select time and grid spacing of the data from 3 to 24 hourly and 1/2 or 1 degree. At present the data available are wind, pressure and precipitation. There is on screen indication of the file size although, if you look at data up and downloaded on your cell phone display, it will be somewhat larger..

Usefully, it is possible to restrict the file size Basically, the software gives a sample of data with your selected element and time interval. It is nearly as flexible as SailDocs and easier to use than email services It is much more flexible than several other systems, free or commercial The data are displayed instantly on the very clear viewer and are always saved for future use or with another viewer if required. Unfortunately, there are no latitude/longitude lines. Requests are replied to within a very short time scale, less than a minute.

I am told that it is suitable for us with Iridium as cell phones.


UGrib selection display

The UGrib selection screen looks like this. The area is selected by hitting the wind arrow and then dragging the pointer across the screen. The area chosen is confirmed by the numbers in the area selection boxes "Area Selection". Areas can be saved for future use. As an alternative, you can enter or

amend the lat/lon in the boxes. For the area shown,
1 degree spaced data at 6 hour intervals for 5 days, the download will be 21 kB. Selecting "Limit file size" allows the user to define the maximum download. This is an important feature when using cell or satellite phone.

UGrib request panel

  UGrub request

Click on picture to enlarge

After hitting "Download Grib File", you are told to wait, a message appears at the bottom of the screen saying that files have been downloaded to the folder of your choice. The file will then open automatically in the viewer as shown here. The blue areas are areas of rain. These will show as areas of organised

rain as in a front or rather indeterminate areas when there are showers. This picture shows a weak front There is an animation option if required. The data can be recovered later by using "Open a Grib file".

UGrib forecast from this request

 UGrib display

Click on picture to enlarge


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