Directional Icon
Directional Icon is an attempt to display direction from user's point of reference to another object in space.
It uses the idea of ship's compass.
User's heading is along the z axis, facing in the direction from Sol to the Galactic Core (looking at Sagittarius A*),
so that "Above" the galactic plane (the direction in which "y" coordinate increases) is above and "left" (the direction in which "x" coordinate increases) is to the left.
The blue circle ( or ) indicates the direction to the object.
If the object is "in front" of user, the blue circle will be solid (), if it's "behind", then it will be hollow ().
If no system is given as user's point of reference, Sol will be used as one (coords: 0, 0, 0).
Example:
For this demo user's point of reference has coordinates 0, 0, 0
The vectors below are to points with different x, y, z coordinates:
Table 1: z=-1
| y\x | x=-2 | x=-1 | x=0 | x=1 | x=2 |
| y=-2 | | | | | |
| y=-1 | | | | | |
| y=0 | | | | | |
| y=1 | | | | | |
| y=2 | | | | | |
Table 2: z=0
| y\x | x=-2 | x=-1 | x=0 | x=1 | x=2 |
| y=-2 | | | | | |
| y=-1 | | | | | |
| y=0 | | | | | |
| y=1 | | | | | |
| y=2 | | | | | |
Table 3: z=1
| y\x | x=-2 | x=-1 | x=0 | x=1 | x=2 |
| y=-2 | | | | | |
| y=-1 | | | | | |
| y=0 | | | | | |
| y=1 | | | | | |
| y=2 | | | | | |