What does geographical knowledge (weather) F mean?

The wind level, f is 1 vertical bar and 2 horizontal bars, representing 5-6 winds.

1- level 2:? 1? Vertical bar? 1? Horizontal?

Level 3-4:? 1? Vertical bar? 2? Horizontal?

Level 5-6:? 1? Vertical bar? 3? Horizontal?

Level 7-8:? 1? Vertical bar? 4? Horizontal?

Grade 8 or above: 1? Vertical bar? 1? Triangle? Like a little flag?

Wind direction: Wind direction indicates wind direction. For example, (1) indicates the southwest wind with 7-8 grades, and the wind blows from southwest to northeast. (2) It means that the northeast wind with grade 7-8 is blowing, and the wind blows from northeast to southwest.