Complex sentence: But the tangent cannot distinguish between, let say an azimuth of 45 ° and 225 °, while these two values are very different, they are opposite directions, NE and SW respectively.
Split into simpler sentences: But the tangent cannot distinguish between (for example) an azimuth of 45 ° and 225 °. These two values are very different: they are opposite directions, NE and SW respectively.