Wind barbs · Unknown direction
Known speed retains its value without inventing a heading.
Use wind barbs for observations with numeric X positions and wind speed. Y shows speed in metres per second. Direction is where the wind comes from: 0° north, 90° east, 180° south, 270° west. Rotating or reversing a data axis does not rotate the compass.
Supply numeric axes and up to 16 series of {id, x, value, direction}; at most 2,048 points. value is speed from 0 to 150 m/s or null; direction is [0, 360) degrees or null. Missing speed creates no mark. A diamond means known speed with unknown direction; a ring indicates calm.
Symbols round speed to the nearest five knots: a half barb is 5, a full barb 10 and a filled flag 50 knots. The tooltip retains original m/s and direction. Numeric zoom/pan, reference lines, series colours, axis titles, labels and interactive legends are available. No shared tooltip, point-colour overrides or stacking.