What is this line coming from the light source and how do I adjust it? Forgive me for this noobish question (still learning ropes of blender) but I'm playing with some of the lights properties, and was wondering what this line is and if there is a way to adjust the length of it. I've circled the line in red in the photo. Currently it surpasses my landscape, and it's kinda unappealing being so long. The lights are area lights. Any help would be greatly appreciated.
That line indicates the direction of a sun lamp.
If you rotate it it will determine the direction for the light and shadows.
Note that for sun lamps the placement in the 3d environment is irrelevant, they just have direction.
To control the size of the line (and it is just an informative line line for you to see the direction) just scale it (press S and drag the mouse)