The present continuous is essentially used in the English language to denote an action that is currently being undertaken.
Any action that is likely to be undertaken in the future cannot be denoted by the present continuous.
The reason for this being, though the action is planned, circumstances in the future may result in the action not actually taking place.
As a result the possibility of its non-occurrence is as much as its occurrence.
For example, most people say 'I am coming to your house in the evening'.
This is incorrect because even though you may have planned to visit your friend, many reasons can prevent you from doing so, including bad weather for one.
Therefore you would use 'I am coming to your house', ONLY if you are already on your way there.
If not, while referring to the future it is more appropriate to use a modal auxiliary (the modal auxiliaries include can, could, shall, should, will, would, may, might, must, ought to, used to and dare to), which shows a possibility rather than a certainty along with the action you wish to undertake.
So the correct usage in this case would be: 'I will come to your house in the evening' (the unsaid being, 'circumstances permitting')
It is also important to realise that the present continuous, as we often use it is a literal translation from native tongues, where we use the phrases 'aane wali hoon' or 'aane wala hoon' to denote the future.