Weather | 93
15 Weather
GRIB Weather
GRIB is the format used by the meteorological institutes of the world to transport and
manipulate weather data. You can import GRIB files via an SD card inserted into the card
reader, and overlay the information onto your charts.
GRIB Symbols explained
Zero knots / Indeterminate wind direction
Wind direction Small Barb value = 5 knots
Wind Direction Large Barb value = 10 knots
Wind direction Arrow Barb value = 50 knots
Wind Direction 2 x Large Barbs 1 x Small Barb = 25 knots
The wind tail indicates the relative wind direction from 0 to 359º. Wind speed is indicated
by a combination of small and large barbs at the end of the wind tail. If a combination
of 5 and 10 knot barbs are shown on a tail then these will need to be added together to
give you the total wind speed. The example below left shows 3 x large barb + 1 x small
barb = 35 knots. Below right shows 60 knots in a different direction, 1 x 50kn arrow + 1
x Large barb.
Direction
Large Barbs
Small Barb
Large Barb
50kn Arrow
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