The intermediate directions are between the cardinal directions. They are NE for northeast, SE for southeast, SW for southwest, and NW for northwest. On a compass rose, these are usually indicated in between the cardinal directions and illustrated by many smaller points emerging from the center of the starburst shape in a compass rose.
The most graphic example of intermediate directions is shown in a compass rose, a directional indicator included in most maps and globes to orient the map viewer to the landscape pictured. The rose probably received its moniker due to the elaborate style in which many cartographers inscribed it on their maps. The compass rose is a multi-pointed, four-quadrant diagram that always shows at least one of the cardinal directions (N for north, S for south, E for east, and W for west). The rose generally also shows the intermediate directions as additional points emerging from the center, though they may not necessarily be marked as such.
Travel directly north or directly south requires travel along a line of longitude. Lines of longitude are called "meridians," and there are many more of them than a globe will show you. Similarly, direct east-west travel requires moving along a line of latitude (also called a "parallel"). When you're not moving absolutely north-south or absolutely east-west, you're traveling in an intermediate direction.
Early navigators used the sun and the direction of the prevailing winds to find their way. The earliest, wind-based names for directions (i.e. levant, sirocco, and greco) are for the most part lost, but the compass rose may very well have been developed by ancient sailors from these wind patterns. The early Romans are credited with adding the intermediate directions to the four-point system. Many historians believe the credit for inventing the first magnetic compass goes to the Italian Flavio Gioia.
The compass began with the four cardinal directions. The rest of the points were added in order to give navigators more precise bearings. Finally, navigators were using compasses that included 32 total cardinal and intermediate directions. When all 32 points are recited, the speaker is said to be "boxing the compass." Interestingly, the recitation begins at the east and not the north; in relation to Western Europe, where the compass was invented, Jerusalem was in the east. For religious reasons, the inventors thus considered east the primary compass direction.
A 32-point compass rose, of course, includes many more intermediate directions than the simple SE, SW, NW, NE midpoints. The names of the rest of the intermediate directions are formed by taking the initials of the cardinal directions and adding them to the closest intermediate directions. (A highly recognizable example of this naming system in use is the title of the Hitchcock movie "North By Northwest".) These names, though given in English, are internationally understood, and navigators worldwide use them to refer to headings when it's inconvenient to recall degrees.
