What is the mean of 'samma ditti' in Ariya-Ashtanga Marga?

Everybody, who is learning Buddhism know that **'Samma Dhitti'** is the 1st of **'Ariya-Ashtanga Marga'**. It's surface meaning is 'Right vision'. But what is the exact meaning of it? It is a one procedure of 'Ariya-Ashtanga Marga' to achieve 'Nirvana'. I want to know the deep meaning of it. How to achieve right vision or Samma Dhitti? Is it a procedure of our thoughts? If we go to the *'Samma aajeewa','Samma kammantha','Samma wacha''Samma wayama'*, we can describe them as procedures or habits. But I get a feeling that 'Samma Dhitti' is more than that.