_____ _ _ _ |_ _| _| |_ ___ _ __(_) __ _| |___ | || | | | __/ _ \| '__| |/ _` | / __| | || |_| | || (_) | | | | (_| | \__ \ |_| \__,_|\__\___/|_| |_|\__,_|_|___/ _ ___ ____ (_)/ _ \/ ___| | | | | \___ \ | | |_| |___) | |_|\___/|____/
Note that this tutorial will use an iPad for its images. The process is very similar on iPhone, with a little more scrolling.
LuckGrib on iPad is preferred over iPhone, for people serious about weather.
The first step in getting started using the Offshore Data product is to start your free trial. This is done by opening the Library:
And then tapping on the ‘In-App Purchase Store’.
You will then see the following window:
When you tap on the large blue button on the left, you will be guided through a standard Apple in-app purchase process. During this process, the price (free) will be confirmed. Accept the “purchase” of the free trial to get started.
I suggest that before starting this free trial that you have access to the hardware you intend to use for your downloads, as well as access to your offshore email account.
Also, if you are new to the application, it may be worthwhile using it for a little while before starting this free trial.
This is done in the application Settings, accessible from the Library (as shown in the first image.)
Tap on the Download method row to see a selection of the download methods available.
If you choose the email or low speed internet options you have the option to set the maximum file size. When the server is creating your Offshore file, if the resulting file becomes larger than this limit, then only the portion of the file that fits into the space allowed will be sent.
If you are using the email option, then both the approximate file and email size are provided. (When binary data is sent via email it must be encoded in ASCII, and this process causes the file to become larger.)
When downloading files via the Offshore Data service, you will want to carefully control the amount of data you are asking for. An important part of this will be specifying the region for the data you want to download. The normal method of downloading the region covered by the visible area of the screen is still available or course, but you will probably want finer control over this.
To specify the region, first select the Region tool, the rectangle tool at the top left in the image below:
Then, use the tool to create the region you want:
There will be opportunities to adjust this region later, if you wish.
If you are sailing, I suggest that you use the Location function to have your current location shown. You can use this location to properly orient the region you create. (Tap on the blue Location button to the left of the position shown in the image above.)
If this is the first request for this area, you will need to create a GRIB request for it. If you already have a request, you can simply adjust its region to correspond to your current needs.
You have a selection of a large number of GRIB models to choose from, including ocean wave and ocean current models. For example, tap on the GFS row in the image above to move to the Model Selecion area. (Ocean waves and currents are available, along with many other models.)
Choose the parameters you want to download. You will probably want to limit the number of parameters to a select few, to keep your files small.
In the image shown above, you have the ability to change the resolution of the file download. On the open ocean, often even a 1° resolution is sufficient. Adjust the resolution, forecast hours, forecast duration and region until the estimated file size looks appropriate.
I prefer to give each request a filename, so that they are more easily identified in the file list (if you receive this data via email, this file name will appear in the subject line.)
Finally, click on the Download button to move onto the request processing stage.
If you are on a moving vessel, you can often re-use the same request, as long as you modify its region to keep up with you. This can be done quite easily.
To get to this area, follow these steps:
At this point, you can edit the region with several options, as shown.
you can nudge the region north/south/east/west in one degree increments by pressing the arrow buttons. Often this quick adjustment is all you will need to do
you can more accurately specify the size of this region by giving it a width and height. Note that the width and height are specified in a distance unit, not in degrees of latitude/longitude. This can make a big difference when you are in the higher latitudes
if you are on a moving vessel, you can specify its heading and the distance travelled since you last updated this region, and have LuckGrib calculate a new location for the region
lastly, if you prefer to work interactively, you can copy this region to the Region Tool, dismiss these windows, adjust the region interactively, come back to this window and then copy the new region you just created to this request
When you are finished modifying this request, move back to the previous screen and tap on the Download button to submit this request and see the email details.
At this point, if you are following along this tutorial on your own copy of LuckGrib you will be looking at a screen holding details of either an email or low speed internet interaction.
There is one more detail to cover before discussing those screens in details.
If you want to download more than one file, that is possible in LuckGrib.
You may not have discovered it yet, but the Library area can be displayed by doing a swipe gesture from the left edge of the screen into the middle. If you do that after sumitting one request to the Offshore system, then you can add additional requests to the queue before proceeding with the file download.
For example, in the image above, the small gfs file is another file I had setup as a suitable Offshore Data request. If I tap on its Refresh icon, it will be added to the queue.
You can also remove items from the queue at this point, by tapping their Cancel icon. For example, the image above is showing the ‘hawaii-gfs’ request is pending in the queue. If you were to tap its Cancel icon, it would be removed.
At this point, the interaction is slightly different, depending on how you are going to obtain your file: