I honestly can't figure out what that radar is trying to tell me.
As blowfish pointed out, the region you fly in, like the radar, is on a sphere.
Single-pixel dots on the radar are on the far side, and X-shapes are on the near side.
Blue represents jump gates. Or wormholes. Or whatever they are.
Shades between green and red are ships with varying degrees of damage. The original reasoning behind having it like this (instead of based on what team the ships are on) was because this way it forces you to get a visual on them before firing. Nonetheless, the AI is simple enough that if you know what team at least one of them is on (preferably a friendly one) you can track how they move relative to one another and figure out what teams they're on.