Importing wind forecasts from grib.us into VRTool with GribToXML.

Note: Since the release of this application, I tested another one, developed by BobZhang, that does a similar job, but produces xml files that match game data much closer. It is called Grib2XML (not to be confused with GribToXML described in this page). While GribToXML simply decodes the grib file to raw values, Grib2XML probes the grib file and does some extra processing. I don't know the details of it, but it works. BobZhang´s Grib2XML can be found in this URL.

VRTool cannot read grib files directly. To import grib forecasts into VRTool, data needs to be converted to a flavor of XML accepted by the program. For that you can use the program GribToXML, described in this page.

GribToXml uses the NOAA degrib application to decode grib files to text. Then it reads the output and generates a Xml file in a format accepted by vrtool.

Not all grib files are equal. There are two versions of grib files. NOAA degrib can decode grib2 messages. Also, grib files can contain arbitrary resolutions, forecast intervals, number of forecasts. Forecast positions may not fall in integer Lat, Lon boundaries.

Grib.us

One popular grib source is www.grib.us. The UGrib application downloads grib files and saves them to a local directory, before displaying. You can import those files to vrtool and extend the wind forecasts up to 7 days (or 168h).

VRTool can load 3hs and 6hs forecasts, with resolutions different from 1.0 degree, but these are of little use when compared to game wind files (interval=12h, resolution=1deg, up to 72h). In order to obtain the best results, use the following configuration when downloading with Ugrib:

Use integer degree values for lat/lon in Area Selecion In Grid data options, use 7 days and 12h intervals Resolution = 1.0 degrees Parameters : Winds only

Ugrib application options

note: Other grib sources are not supported at this time.

Installing and using gribtoxml

1) Download the installer file using the link below and save to your Windows desktop.

3) Run the program using the [Start] > Applications > VRTool > GribToXml menu.

4) Click button [Convert .grb --> .xml]

5) Select the grib file (saved previously by UGrib) and click ok. Converting grib files might take some time.

6) When prompted, type xml file name and click ok to save.

7) To load the xml file with VRTool. Use the menu option Winds > Load Xml.

For more information on degrib, go to ndfd degrib homepage