I asked Udo Okonjo a Do Something Mentor,
@UdoOkonjo please say, Are purpose and vision one and the same thing? #DSmentor
She was kind to answer:
Purpose is your WHY? Your core reason for existing as a person/biz. Vision is your dream, your aspiration, your WHAT’s possible? – Udo Okonjo
Do visit her blog, udookonjo.com, great practical stuff there.