You sense the presence of any trap within range that is within Line of Sight. A trap, for the Purpose of this spell, includes anything that would inflict a sudden or unexpected Effect you consider harmful or undesirable, which was specifically intended as such by its creator. Thus, the spell would sense an area affected by the alarm spell, a Glyph of Warding, or a mechanical Pit Trap, but it would not reveal a natural weakness in the floor, an unstable ceiling, or a hidden sinkhole.

This spell merely reveals that a trap is present. You don't learn the Location of each trap, but you do learn the general Nature of the danger posed by a trap you sense.