As tomndebb’s link says, if North is 0° and East is 90°, then Northeast is 45°. Halfway between North and Northeast, at 22,5°, is North-Northeast, and halfway between Northeast and East, at 67.5°, is East-Northeast. Halfway between North and North-Northeast, at 11.25°, is “North by East” (because it’s North with a bit to the East). Halfway between North-Northeast and Northeast, at 33.75°, is “Northeast by North” (because it’s Northeast with a bit to the North). Halfway between Northeast and Eath-Northeast, at 56.25°, is “Northeast by East,” because it’s Northeast with a bit to the East, and so on.