Usage of supposed to/opposed to

[sucucas]

Can someone explain the use of "supposed to" "as opposed to"?

Thanks!

[Anglika]

He is supposed to go to the doctor today. >> It is expected that he is going to the doctor.

We are opposed to the idea of a new town in the fields behind our house. >> We are against this idea.

[sucucas]

Thanks so much for your examples. Can I also say: I am supposed to be sad as opposed to be happy? or Are you going to vote for .....as opposed to....? This is what confuses me most.....

[Anglika]

Thanks so much for your examples. Can I also say: I am supposed to be sad as opposed to be happy? or Are you going to vote for .....as opposed to....? This is what confuses me most.....

Yes, you can - it has a different meaning from my example:

I am supposed [meant] to be happy as opposed to being sad [here "opposed" is "rather than"] >> I am meant to be happy rather than sad.

Are you going to vote for X as opposed to Y? >>Are you going to vote for X rather than Y?