What is the sense of 気配がする (けはいがする) versus 気がする?


I'm (trying) to read a Japanese spy novel at the moment. It could just be the
author's style, but I see lots of sentences end in 〜気配がする。

The more I read, the more I wonder - is there any difference between this and
気がする?

> 一人で公園のベンチで本を読んだら、隣にだれか座ってきた気配がする。
>
> 一人で公園のベンチで本を読んだら、隣にだれか座ってきた気がする。

The above example is mine, but it was the context of the book (I am too lazy
to go find the page now).

A cursory look in the dictionary tells me that 気配 is more like "sense" whereas
the latter may be more like "feeling" \- anyone care to help?




気配 is defined in
[大辞泉](http://dic.yahoo.co.jp/dsearch?enc=UTF-8&p=%E6%B0%97%E9%85%8D&dtype=0&dname=0na&stype=0&pagenum=1&index=06954405654400)
as something which is "not clearly seen, but vaguely sensed." It is used to
describe an indication or hint of something outside the person who senses it,
and shows up in more patterns than just 気配がする:

> 人の気配を感じた。 I felt the presence of someone.
>
> 秋の気配がする。 The first signs of autumn appear.

You cannot replace 気配 with 気 in the above examples.

気がする, on the other hand, always refers to the subject's intuition or
suspicions:

> どこかで会ったような気がする。 I have a vague feeling we met somewhere.
>
> 前にこんなことがあった気がする。 I feel like something like this happened before.
>
> これから始まるという気がする。 I have a hunch things are going to start now.




気配 is defined in
[大辞泉](http://dic.yahoo.co.jp/dsearch?enc=UTF-8&p=%E6%B0%97%E9%85%8D&dtype=0&dname=0na&stype=0&pagenum=1&index=06954405654400)
as something which is "not clearly seen, but vaguely sensed." It is used to
describe an indication or hint of something outside the person who senses it,
and shows up in more patterns than just 気配がする:

> 人の気配を感じた。 I felt the presence of someone.
>
> 秋の気配がする。 The first signs of autumn appear.

You cannot replace 気配 with 気 in the above examples.

気がする, on the other hand, always refers to the subject's intuition or
suspicions:

> どこかで会ったような気がする。 I have a vague feeling we met somewhere.
>
> 前にこんなことがあった気がする。 I feel like something like this happened before.
>
> これから始まるという気がする。 I have a hunch things are going to start now.

