Chord Ontology:Development

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.

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 ? 
 * 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.

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)
 * Specify : semantics of base_chord relations, and the 'shorthand' symbols (eg. using  rather than )
 * Depending on who you ask, these are either :
 * 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.


 * 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)

Extra information in symbol service descriptions

 * Add : Guitar tab information to chord descriptions
 * See http://lists.w3.org/Archives/Public/www-archive/2001Nov/0033


 * Add : Score snippet images to chord descriptions
 * Done and live now, courtesy of [Christophe Rhodes] at Goldsmiths
 * eg. 


 * 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

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

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