Importing NOAA Winds

The winds used in the VR and VORG games are generated from weather GRIBs downloaded from NOAA's Global Forecast System. This weather is then processed by the game servers and fed to the game clients on players machines at the regular 12-hourly weather updates.

VRTool is able to import these same weather GRIBS imported directly from the NOAA server, independently of the game. This has the obvious competitive benefit that VRTool has updated forecasts well in advance of the 12-hourly game feed, allowing players to make early course adjustments for the future weather.

Winds are imported using VRTool's built-in NOAA Import Module. There are various configuration settings in the module to ensure that the correct forecasts are extracted from the NOAA server, and that the subsequent processing is consistent with the game servers.

The NOAA Import Module is started by clicking the Winds button on the main toolbar. (The same button is also available on the Wind Grids control panel in the "Winds" tab.)

Setting the GRIB Boundaries

With a broadband connection it is practical to download a very wide area of ocean. This means that even for a trans-oceanic leg you can set the GRIB boundaries once to cover the whole area of the whole leg, and then not touch it again. The module defaults to the last-entered boundaries. This simplifies both the downloads and the weather routing.

Zoom the chart out so that you can see the whole area of the leg.

Start the NOAA Import Module and go to the Download from NOAA tab. Click on the top-left boundary handle. Now go to the chart and place the cursor at the top-left corner of an imaginary rectangle which surrounds anywhere you are likely to be during the leg. Click to pick up the co-ordinates of this point. Then do the same for the bottom-right corner. The GRIB boundaries are now set for the whole leg.

(add a tip here about crossing the 180° meridian)

VORG 2011-2012 Settings

Download Parameters

Time Zone: Set this to your computer's time zone setting. You can click on the icon to retrieve this automatically. (Not sure what VRTool does with this.)

Tip: For users in the GMT +12:00 zone (eg New Zealand), clicking on the icon retrieves a system time zone of -12. The -12 setting seems to work correctly.

Resolution: Set to 12. This is the forecast interval in hours. (Not sure what VRTool does with this.)

Up to: Determines the number of forecasts downloaded. A setting of 180 will download all the forecasts up to and including the +180 hour forecast. The normal maximum is 180 hours. Reduce this setting if you know you will reach your destination in less time - this speeds up the download (and has another more important benefit).

Transformations

These settings ensure that the downloaded GRIB is processed in the same way as the game server, so that VRTool's weather is indentical to the game weather.

The Grid Probe Resolution (set to 1°) sets the resolution of the data points in the downloaded GRIB file. These weather data points are displayed on the chart at 1° intervals. For the VORG the speed and direction are then interpolated between these points, so it is important to ensure that wind interpolation is turned on in VRTool.

Running the Download

To run a manual download click on Download Now!

VRTool can also be set up to do automatic downloads. However manual downloads are very simple, and give you opportunity to observe the download and verify that it has completed correctly.

The progress of the download and conversion to .XML format can be observed in the module window. If the download is interrupted it usually means that the NOAA GFS run is still in progress and the forecast file is not yet available. This is discussed in more detail in ????. If this happens wait for a while and try again.

After each download is complete and the weather appears on the chart you should always:

• Click on the forecast selector in the toolbar. This is because the chart does not alwary refresh correctly after a new download.
• Display the current weather (by clicking on the 0h weather in the forecast selector. Use the Ruler or Route tool to read the weather at some location - your current boat position is a good place. Then go to the samelocation in the game client window and check the wind speed and direction are identical.

Advanced Topics

Time Zones

Time zones can be confusing. Real mariners keep a clock set to GMT. Similarly life in virtual regattas is much simpler if you set your game computer to the GMT time zone. However this may confuse some other applications, such as email clients.