seeing the chords on top of scale patterns

The image below is showing the major scale pattern in the key of G.
If you want to try to play the 7 possible triads within G major, this chart makes it easy to see which chords fit in where!


The I, IV, and V chords are all major, and the II, III, and VI chords are minor.  The VII chord is a minor, but with a flatted fifth - since F# minor would have a C# in it.  G major doesn't have C# at all, so the chord gets a diminished kind of sound.

So far, looking at the chords this way on top of the major scale has really helped to pick out the arpeggios when I'm in a scale.  The chart helps to see where to aim in the scale when you're in a major key that matches a chord progression (for example, if the song has a part with the chord pattern: G D Am C, you could focus your lead guitar's soloing to the I, V, II, and IV notes shown in the image above).

These patterns aren't just restricted to the key of G - you can slide this left or right by any amount of frets, and the patterns remain the same - it is just the key of the major scale that changes. 

Many songs don't stay in the same key signature for long, but knowing where to play when the key signature is well-defined is critical if you want to clean up your soloing and improvisation while jamming.

Enjoy!

TIPS: 

- Try to fill in the names of the notes on the above image - each chord is only 3 notes, repeated over and over again in the patterns.  By doing this, you'll be learning the next level of detail (which note is which, and where octaves of each note can be found) - and once you are comfortable with that, playing scales along with any chord progression can be mastered!

- Practice these same patterns in key signatures other than G major.  Just slide the whole major scale pattern to match the fret you wish to be your root note - everything else stays the same!

One, Four, Five!

Here's a way to find out what key a song is in while playing along (and a little music theory)...

Just remember that for any Major key, the first (I), fourth (IV), and fifth (V) notes are always going to be major.  So consider the key of C.

C Scale:     C    D    E     F    G    A    B
Number:     I     ii     iii     IV   V   vi    vii

So we have the One, Four, Five for C major:  C F G

Lets say you're listening to a song, and you can tell it has an A major chord in it.
Using this method, you can quickly find out which key the song is in, and then you'll know which scale to play to fit in.

There are three places this A major chord could fit into the scale, either the first, fourth or fifth position...

1 4 5                   I   ii     iii      IV  V   vi      vii                1 4 5
A _ _   A major (A  Bm  C#m  D  E   F#m  G#m) ==> A D E   is the 1,4,5 for A major
_ A _   E major (E  F#m G#m  A  B  C#m  D#m) ==> E A B  " " " " " " " " " " " E major
_ _ A   D major (D  Em   F#m  G  A  Bm    C#m) ==> D G A " " " " " " " " " " " D major

So from here, you'd want to try to find more chords in the song's progression, and you can narrow down this short list.

Similarly, if all you can find is a minor chord in the song, there will be 4 places in the scale the chord could fit.

Let's say Dm, now we're dealing with 2nd, 3rd, 6th, and 7th positions in the scale (takes a little more time and memorization than the major chord/scale).

2    3 6 7                            I    ii       iii      IV  V   vi      vii                 1  4  5
Dm _ _ _  ==> C major   (C   Dm   Em   F    G   Am   Bm)   ==>    C F G
_ Dm _ _  ==> Bb major  (Bb Cm   Dm   Eb  F   Gm   Am)   ==>   Bb Eb F
_ _ Dm _  ==> F major    (F   Gm   Am   Bb  C   Dm   Em)   ==>  F Bb C
_ _ _ Dm  ==> E major    (E   F#m G#m  A   B   C#m Dm)   ==>    E A B


Practice Tips: 
Try to do the exercise above for another chord other than A major or Dm. 
Try to figure out the chords to a song by ear.

Also,
Play the scale of the key you want.
Then, try to play the chords at each note of the scale. 
Try to mix up which chords are major or minor as you go up the scale, and see how it sounds if you change from the 1,4,5 pattern shown above.  (MAJOR minor minor MAJOR MAJOR minor minor)

Example:
play first the notes: C D E F G A B
then play the chords: C Dm Em F G Am Bm
now see how it sounds to play these chords: C D E F G A B (all major)
or try any other variation from 1,4,5 being major.