The present continuous for the Future and Going to

We use the present continuous and going to + infinitive to talk about future activities and events that are intended or have already been arranged:
• She's making a speech at the conference next week.
• Are you seeing Tony this week? (= do you have an arrangement to see him?)
• I'm tired. I'm not going to work any more tonight.
• We're going to do some climbing in the Pyrenees.
We don't use will to talk about arrangements and intentions
Apparently, the council are closing / are going to close the old library. (= reporting an arrangement) (not ...the council will close...) When we talk about an INTENTION to do something in the future, although no definite arrangement has been made, we prefer going to rather than the present continuous. To emphasise
that we are talking about a DEFINITE ARRANGEMENT, we prefer the present continuous.

We don't use the present continuous for the future:
• when we make or report predictions about activities or events over which we have no control (we can't arrange these):
• I think it's going to rain / '11 rain soon, (not I think it's raining soon.)
• Scientists say that the satellite is going to fall / will fall to Earth some time this afternoon. (not ...the satellite is falling...)
   when we talk about permanent future situations:
• People are going to live / will live longer in the future, (not ...are living...)
• The brothers are going to own / will own most of the buildings in the street before long. (not ...are owning...)
• Her new house is going to have / will have three floors, (not ...is having...)
   with the verb be:
• John's going to be a shepherd in the school play next week, («of John's being...)
• I'm going to be in Tokyo in May. (not I'm being in Tokyo...)
We tend to avoid going to + go and use the present continuous form of go instead:
• I'm going to town on Saturday, (rather than I'm going to go to town...)
• Alice is going to university next year, (rather than ...is going to go to university...)