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Why are there two wind options, Wind (0-36) and Wind (0-40)?

April 26, 2017Options wind

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Why are there two wind options, Wind (0-36) and Wind (0-40)?

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Both options provide wind direction and wind speed information. The direction is defined by the secondary y-axis on the right side of the chart. The 0-40 option is the most used wind direction charting option. In this case the direction data is scaled so that the compass points correspond with the 5 mph grid lines on the chart. The 0-36 option is a good choice for people that are comfortable thinking of direction in terms of degrees (0-360). 180 degrees on the right axis corresponds with 18 mph on the left axis; a scaling factor of 1/10. One frequent user, a sailplane pilot, prefers this wind charting option. In either case, the secondary axis makes it straightforward to interpret the direction data. For the curious, some history and development details: The chart-imagemodule used in Waconia (ASPChart) unfortunately does not have an option for a secondary y-axis. The secondary axis that you currently see is actually a hand-built static image (a transparent gif), overlaid on the chart.