Vision is "the dream" of mission in longer time in broader perspective of what the organisation will be come.
The effort working the mission with knowing what it should be, likes within next 15-20 years, put a positive tension to mission to keep on track. As a child want to be a famous doctor, he/she need mission to work on to achieve the goal i.e. graduated with good score on related subject, choose to go to university with majoring in doctor, etc. The vision of the child direct the mission selected and achieved to make the child a doctor.
The vision is inspirational enough for the organisation knowing what the organisation can become, can do, can build, can established, or can dismantle, can leave behind. Vision is always about imagining positive state and condition of the future but it must be concise, consistence with mission, and feasible.
The vision provides performance with direction for improvement and what can be achieved in the future.
Until next time - Be wise, Be successful!