Chord Ontology:Development

From Music Ontology Wiki

Jump to: navigation, search

Contents

[edit] Introduction

The current Chord Ontology ('draft 1') is described at http://purl.org/ontology/chord/ (or http://purl.org/ontology/chord/draft1/ in perpetuity).

This page is for summary and discussion of proposed changes or additions for draft 2 of the ontology.

[edit] Proposed changes

[edit] Changes to the chord description model


  • Fix : Allow unnamed root note - Currently intervals may be pitch class rather than named note, by using a SemitoneInterval rather than a ScaleInterval, but the same cannot be done for the root of the chord.
    • How to specify pitch of root ? Number 0-11 with 0=C ? see also point below about attaching notes to intervals.



  • Add : Allow root to be specified as a degree of the key
    • "One thing I think might be missing is to allow scale degree notation as is very common in musicologists' work, i.e. they describe C Em F Ab as I iii IV bVI" -- MatthiasMauch



  • Add : Explicit information about where chord information has come from.
    • This should be possible to infer from context
    • but explicit labelling like "human annotation", "machine annotation", "musical score" might be helpful in some situations ?
    • Specifying a confidence value in a chord:ChordEvent or chord:Chord instance might also be helpful



  • Add : Specification of chord voicing
    • Common in jazz to specify eg. open vs. closed. vs. mixed voicing



  • Add : Associate intervals of a chord with actual note resources
    • Possible tie-in with the symbolic notation ontology ? <http://motools.svn.sourceforge.net/viewvc/motools/so/>
    • This could help with the 'unnamed root notes' issue above
    • This also removes the need for the chord ontology to cover specification of component notes by octave and pitch class (as had been suggested)



  • Add : Higher level information about the functions of chords
    • Incorporating work from our colleagues Tillman Weyde and Jens Wissmann at City should take care of this nicely



  • Issue : Metrical time
    • Hopefully this will be developed further in either the TimeLine or symbolic notation ontologies.



  1. Just a shorthand so you can type C:maj7 instead of C:(1,3,5,7)
  2. An additional semantic label, specifying the interpretation of the coincident intervals (1,3,5,7) as a major seventh chord.

Personally I feel only the second option has any place in an RDFS ontology, and I think we need these semantically-weighted labels in the ontology. Taking this interpretation means that some of our data (eg. the Beatles transcriptions) must be re-converted because the original use of the shorthands in Chris Harte's notation does *not* necessarily imply any interpretation on the intervals. --Chris Sutton 15:58, 3 December 2007 (CST)


  • Reconsider the name ScaleInterval
    • Perhaps misleading - eg. is the ScaleInterval with degree 3 in a major chord different from the ScaleInterval with degree 3 in a minor chord ? (answer: no, but the name suggests in might be)



[edit] Extra information in symbol service descriptions






  • Reconsider : chord symbol service notation
    • This was originally taken directly from Chris Harte's notation, switching the '#' for a 's'
    • Would be better to avoid using '/' for bass notes
    • Might be better to avoid commas



[edit] Documentation


  • Add : Use case descriptions
    • We have a few use cases which could be written up
      • At QM : conversion from QM notation .lab files, mma files, or Goldsmiths notation CSV files for consumption by Java chord analysis suite
      • John Ibbotson's work on semantic analysis of MIDI streams
      • any others so far ?
      • Danny suggested :
        • transcribe chordal music ?
        • play it back ?
    • Similar to use cases, some 'classic' chord examples might be useful, to show how you'd describe particular chords using the chord ontology.
      • eg. the ['Tristan chord'] from Tristan & Isolde or some quartile harmony examples



  • Add : tests
    • How to design these ?



  • Add : example data sets
    • mma set should be published



[edit] Other ontologies


See also : Key_Ontology:Development for discussion of describing scales and keys.

Retrieved from "http://wiki.musicontology.com/index.php/Chord_Ontology:Development"
Personal tools