XyGrib FAQ

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• Why am I getting empty Grib files when requesting WW3 data in the Mediterranean?

Answer: The NCEP-WW3 model does not cover the Mediterranean with data. It's grid does cover the area so expect to get empty WW3 Gribs in the Med.

• Why is the map resolution so low and missing shoreline details?

Answer: The XyGrib install package includes maps up to the 3rd resolution of 1km. To get two more levels down to 100m, you should install the hires map set that can be downloaded from the opengribs.org web site. The maps need to be extracted to the data/maps/gshhs/ folder in the XyGrib install area. It is OK to overwrite existing map files.

• Why does altitude data take so long to prepare on the server?

The more parameters in the request the longer the file preparation will be. Skewt and other altitude requests have multiple parameters for multiple levels and therefore can take up to a minute to prepare

• Can the overlay color schemes be changed?

Sure! Look in the data/colors folder for the editable overlay color files. Keep a backup and then try to change the RGB setting of the overlay that you wish to edit.

• Why is the size estimate for the requested Grib file sometimes not quite accurate?

If the requested rectangle includes wave data and is not entirely at sea - then land areas have empty wave data and the file will be significantly smaller than the estimate. Second factor is that the Grib files are compressed (Grib2 internally) and the compression ratio can change in different situations.