sunlove wroteNotion does not support MIDI guitar. The standard for MIDI guitar is 6 different MIDI channel, one per string.
This allows to treat distinctively the same note at the same octave on different string.
Even if you input notes through a MIDI guitar, Notion will mess up the fret position and string every time.

The NOTION 6 User Guide has a different perspective . . .

Multi-Channel Guitar Option

"If you are playing in from a guitar MIDI controller, you will most likely want this option turned
on. MIDI guitars send the notes for each string on a different MIDI channel, and the program
uses this information to put the notes you play on the right string on the Tablature staff."

[SOURCE: NOTION 6 User Guide]

THOUGHTS

There are many types of MIDI guitars, and some of them are more accurate than others . . .

The way the guitar's action and intonation are set is very important, especially with respect to the relative signal strength of each string; and in this regard configuring a guitar specifically for use as a MIDI guitar is likely to be different from the way the same guitar is configured for playing through an amplification system (audio vs. MIDI) . . .

NOTION provides various options for use in configuring MIDI Record to tailor it to a specific MIDI guitar . . .

[NOTE: These are the default settings, with the exception of the "Multi-channel guitar" option, which I checked to make it more relevant to this topic . . . ]



There is a "Chord looseness" option, which allows you to configure the way NOTION recognizes when you are playing a chord, as contrasted to individual notes . . .

Your guitar might have additional options for configuring and so forth . . .

And then there is the matter of the "Concert A" reference tuning pitch, which by American and International standard is 440-Hz . . .

Be certain to use the standard "Concert A" 440-Hz reference tuning pitch, which is specified in NOTION Preferences on the "Audio" tab . . .



Keeping your guitar tuned correctly is important, as is using string gauges and types that produce the best MIDI matching . . .

Generally, I use Ernie Ball strings with a plain (not wound) "G" string, more on the heavy side but not too heavy--most of the time "Power Slinky" strings, but it depends . . .

You might need to do some experiments to determine the best way to configure everything for recording MIDI guitar in NOTION . . .

There are MIDI utility programs that let you see the MIDI produced by your guitar, and this is another way to determine what is happening . . .

It's useful to understand that there is not a one-to-one mapping of MIDI to music notation, so this can be another factor in the grand scheme of everything . . .

Converting MIDI to music notation is a blend of art and science . . .

SUMMARY

There are a lot of variables involved in MIDI guitar, and giving diligent attention to each variable is likely to produce the best results . . .

With a MIDI keyboard, it's trivial because each key identifies a specific MIDI note; but for MIDI guitar it's different, because determining which note maps to a particular vibration on a specific string involves algorithms, not clear and absolute indicators like on a MIDI keyboard . . .

The algorithms that determine the mapping of detected vibrations to specific MIDI notes vary depending on the particular MIDI guitar and its MIDI detecting hardware and software . . .

Perhaps not so intuitively, but nevertheless accurately, I suggest that it's more difficult (a) to map lower frequency vibrations to correct notes than it is (b) to match higher frequencies, which is the case because, for example, on electric bass there are not so many frequencies between the open low-pitch "A" string and the frequencies of the "notes" at the first few frets, which means that if it's off by just a few cycles per second (a.k.a., "Hertz (Hz)") then it's a completely different note . . .

In other words, there is not a lot of what one might call "wiggle room" in the lower frequencies . . .

At standard tuning, electric guitars are one octave higher than an electric bass, which makes it a bit easier to identify notes on an electric guitar; but remember that guitar is a transposed instrument, which means its notes are notated one octave higher than they are played--unless you change this in NOTON Score Setup . . .

[NOTE: Explained another way, transposed notation for guitar means that notes are played one octave lower than they are notated. You see the notes on a treble staff, which tends to make it easier to read; but the notes are played one octave lower . . . ]

Without wandering into another topic, one might suggest that most guitar players think "Middle C" is the note at the third fret of the low-pitch "A" string, but this is wrong . . .

"Middle C" actually is the note at the 1st fret of the high-pitch "b" string, and "Concert A (440-Hz)" is the note at the 5th fret of the high-pitch "e" string . . .

Lots of FUN!