<layer>

Module
Attributes
class, copyof, corresp, cue, decls, def, facs, follows, label, metcon, n, next, precedes, prev, resp, sameas, synch, type, visible, xml:base, xml:id
class(optional)Contains one or more URIs which denote classification terms that apply to the entity bearing this attribute. One or more values from data.URI, separated by spaces.
copyof(optional)Points to an element of which the current element is a copy. Value conforms to data.URI.
corresp(optional)Used to point to other elements that correspond to this one in a generic fashion. One or more values from data.URI, separated by spaces.
cue(optional) Value conforms to data.BOOLEAN.
decls(optional)Identifies one or more metadata elements (other than classification terms) within the header, which are understood to apply to the element bearing this attribute and its content. One or more values from data.URI, separated by spaces.
def(optional)Provides a mechanism for linking the layer to a layerDef element. Value conforms to data.URI.
facs(optional)Points to one or more images, portions of an image, or surfaces which correspond to the current element. One or more values from data.URI, separated by spaces.
follows(optional)points to one or more events in a user-defined collection that are known to be predecessors of the current element. One or more values from data.URI, separated by spaces.
label(optional)Captures text to be used to generate a label for the element to which it’s attached, a "tool tip" or prefatory text, for example. Should not be used to record document content. Value is plain text.
metcon(optional)Indicates the relationship between the content of a staff or layer and the prevailing meter. Allowed values are: "c" (Complete; , conformant with the prevailing meter.), "i" (Incomplete; , not enough beats.), "o" (Overfull; , too many beats.)
n(optional)Provides a numeric designation that indicates an element’s position in a sequence of similar elements. Its value must be a non-negative integer. Value is a positive integer, including 0.
next(optional)Used to point to the next event(s) in a user-defined collection. One or more values from data.URI, separated by spaces.
precedes(optional)Points to one or more events in a user-defined collection that are known to be successors of the current element. One or more values from data.URI, separated by spaces.
prev(optional)Points to the previous event(s) in a user-defined collection. One or more values from data.URI, separated by spaces.
resp(optional)Indicates the agent(s) responsible for some aspect of the text’s transcription, editing, or encoding. Its value must point to one or more identifiers declared in the document header. One or more values from data.URI, separated by spaces.
sameas(optional)Points to an element that is the same as the current element but is not a literal copy of the current element. One or more values from data.URI, separated by spaces.
synch(optional)Points to elements that are synchronous with the current element. One or more values from data.URI, separated by spaces.
type(optional)Designation which characterizes the element in some sense, using any convenient classification scheme or typology that employs single-token labels. One or more values of datatype NMTOKEN, separated by spaces.
visible(optional)Indicates if a feature should be rendered when the notation is presented graphically or sounded when it is presented in an aural form. Value conforms to data.BOOLEAN.
xml:base(optional)Provides a base URI reference with which applications can resolve relative URI references into absolute URI references. Value conforms to data.URI.
xml:id(optional)Regularizes the naming of an element and thus facilitates building links between it and other resources. Each id attribute within a document must have a unique value. Value is a valid xml:id.
(MEI.shared) Attributes that form the basis of the att.common class.
xml:base(optional)Provides a base URI reference with which applications can resolve relative URI references into absolute URI references. Value conforms to data.URI.
(MEI.shared) Attributes that uniquely identify an element.
xml:id(optional)Regularizes the naming of an element and thus facilitates building links between it and other resources. Each id attribute within a document must have a unique value. Value is a valid xml:id.
(MEI.facsimile) Attributes that associate a feature corresponding with all or part of an image.
facs(optional)Points to one or more images, portions of an image, or surfaces which correspond to the current element. One or more values from data.URI, separated by spaces.
(MEI.shared)
label(optional)Captures text to be used to generate a label for the element to which it’s attached, a "tool tip" or prefatory text, for example. Should not be used to record document content. Value is plain text.
(MEI.shared) Attributes that specify element-to-element relationships.
copyof(optional)Points to an element of which the current element is a copy. Value conforms to data.URI.
corresp(optional)Used to point to other elements that correspond to this one in a generic fashion. One or more values from data.URI, separated by spaces.
follows(optional)points to one or more events in a user-defined collection that are known to be predecessors of the current element. One or more values from data.URI, separated by spaces.
next(optional)Used to point to the next event(s) in a user-defined collection. One or more values from data.URI, separated by spaces.
precedes(optional)Points to one or more events in a user-defined collection that are known to be successors of the current element. One or more values from data.URI, separated by spaces.
prev(optional)Points to the previous event(s) in a user-defined collection. One or more values from data.URI, separated by spaces.
sameas(optional)Points to an element that is the same as the current element but is not a literal copy of the current element. One or more values from data.URI, separated by spaces.
synch(optional)Points to elements that are synchronous with the current element. One or more values from data.URI, separated by spaces.
(MEI.shared) Provides attributes for elements which may be associated with particular contextual elements within the header.
decls(optional)Identifies one or more metadata elements (other than classification terms) within the header, which are understood to apply to the element bearing this attribute and its content. One or more values from data.URI, separated by spaces.
(MEI.shared) Attributes used to supply an integer number designation for an element.
n(optional)Provides a numeric designation that indicates an element’s position in a sequence of similar elements. Its value must be a non-negative integer. Value is a positive integer, including 0.
(MEI.shared) Attributes capturing information regarding responsibility for some aspect of the text's creation, transcription, editing, or encoding.
resp(optional)Indicates the agent(s) responsible for some aspect of the text’s transcription, editing, or encoding. Its value must point to one or more identifiers declared in the document header. One or more values from data.URI, separated by spaces.
(MEI.shared) Attributes which can be used to classify features.
type(optional)Designation which characterizes the element in some sense, using any convenient classification scheme or typology that employs single-token labels. One or more values of datatype NMTOKEN, separated by spaces.
(MEI.shared) Attributes which can be used to classify features.
class(optional)Contains one or more URIs which denote classification terms that apply to the entity bearing this attribute. One or more values from data.URI, separated by spaces.
(MEI.shared) Logical domain attributes.
def(optional)Provides a mechanism for linking the layer to a layerDef element. Value conforms to data.URI.
(MEI.shared) Attributes that describe "cue-ness".
cue(optional) Value conforms to data.BOOLEAN.
(MEI.shared) Attributes that provide information about a structure’s conformance to the prevailing meter.
metcon(optional)Indicates the relationship between the content of a staff or layer and the prevailing meter. Allowed values are: "c" (Complete; , conformant with the prevailing meter.), "i" (Incomplete; , not enough beats.), "o" (Overfull; , too many beats.)
(MEI.visual) Visual domain attributes.
(MEI.shared) Attributes describing whether a feature should be displayed.
visible(optional)Indicates if a feature should be rendered when the notation is presented graphically or sounded when it is presented in an aural form. Value conforms to data.BOOLEAN.
(MEI.gestural) Gestural domain attributes.
(MEI.analytical) Analytical domain attributes.
Facsimile component declarations.
facs(optional)Points to one or more images, portions of an image, or surfaces which correspond to the current element. One or more values from data.URI, separated by spaces.
Component declarations that are shared between two or more modules.
class(optional)Contains one or more URIs which denote classification terms that apply to the entity bearing this attribute. One or more values from data.URI, separated by spaces.
copyof(optional)Points to an element of which the current element is a copy. Value conforms to data.URI.
corresp(optional)Used to point to other elements that correspond to this one in a generic fashion. One or more values from data.URI, separated by spaces.
cue(optional) Value conforms to data.BOOLEAN.
decls(optional)Identifies one or more metadata elements (other than classification terms) within the header, which are understood to apply to the element bearing this attribute and its content. One or more values from data.URI, separated by spaces.
def(optional)Provides a mechanism for linking the layer to a layerDef element. Value conforms to data.URI.
follows(optional)points to one or more events in a user-defined collection that are known to be predecessors of the current element. One or more values from data.URI, separated by spaces.
label(optional)Captures text to be used to generate a label for the element to which it’s attached, a "tool tip" or prefatory text, for example. Should not be used to record document content. Value is plain text.
metcon(optional)Indicates the relationship between the content of a staff or layer and the prevailing meter. Allowed values are: "c" (Complete; , conformant with the prevailing meter.), "i" (Incomplete; , not enough beats.), "o" (Overfull; , too many beats.)
n(optional)Provides a numeric designation that indicates an element’s position in a sequence of similar elements. Its value must be a non-negative integer. Value is a positive integer, including 0.
next(optional)Used to point to the next event(s) in a user-defined collection. One or more values from data.URI, separated by spaces.
precedes(optional)Points to one or more events in a user-defined collection that are known to be successors of the current element. One or more values from data.URI, separated by spaces.
prev(optional)Points to the previous event(s) in a user-defined collection. One or more values from data.URI, separated by spaces.
resp(optional)Indicates the agent(s) responsible for some aspect of the text’s transcription, editing, or encoding. Its value must point to one or more identifiers declared in the document header. One or more values from data.URI, separated by spaces.
sameas(optional)Points to an element that is the same as the current element but is not a literal copy of the current element. One or more values from data.URI, separated by spaces.
synch(optional)Points to elements that are synchronous with the current element. One or more values from data.URI, separated by spaces.
type(optional)Designation which characterizes the element in some sense, using any convenient classification scheme or typology that employs single-token labels. One or more values of datatype NMTOKEN, separated by spaces.
visible(optional)Indicates if a feature should be rendered when the notation is presented graphically or sounded when it is presented in an aural form. Value conforms to data.BOOLEAN.
xml:base(optional)Provides a base URI reference with which applications can resolve relative URI references into absolute URI references. Value conforms to data.URI.
xml:id(optional)Regularizes the naming of an element and thus facilitates building links between it and other resources. Each id attribute within a document must have a unique value. Value is a valid xml:id.
Member of
model.layerLikeGroups elements that function as notational layers within a staff.
Contained By
(MEI.shared) Groups elements that function as notational layers within a staff.
ossiaCaptures original notation and a differently notated version *present in the source being transcribed*.
(MEI.critapp) Groups elements that may appear as part of a musical variant.
(MEI.critapp) Groups elements that may appear as part of a textual or musical variant.
lemContains the lemma, or base text, of a textual variation.
rdgContains a single reading within a textual variation.
(MEI.edittrans) Groups elements that may appear as part of editorial and transcription elements in music notation.
(MEI.edittrans) Groups elements that may appear as part of editorial and transcription elements.
abbrA generic element for 1) a shortened form of a word, including an acronym or 2) a shorthand notation.
addMarks an addition to the text.
corrContains the correct form of an apparent erroneous passage.
damageContains an area of damage to the physical medium.
delContains information deleted, marked as deleted, or otherwise indicated as superfluous or spurious in the copy text by an author, scribe, annotator, or corrector.
expanContains the expansion of an abbreviation.
origContains material which is marked as following the original, rather than being normalized or corrected.
regContains material which has been regularized or normalized in some sense.
restoreIndicates restoration of material to an earlier state by cancellation of an editorial or authorial marking or instruction.
sicContains apparently incorrect or inaccurate material.
suppliedContains material supplied by the transcriber or editor for any reason.
unclearContains material that cannot be transcribed with certainty because it is illegible or inaudible in the source.
(MEI.shared) Groups elements that are components of a staff.
oStaffA staff that holds an alternative passage which may be played instead of the original material.
staffA group of equidistant horizontal lines on which notes are placed in order to represent pitch or a grouping element for individual 'strands' of notes, rests, etc. that may or may not actually be rendered on staff lines; that is, both diastematic and non-diastematic signs.
Common Music Notation (CMN) repertoire component declarations.
oStaffA staff that holds an alternative passage which may be played instead of the original material.
ossiaCaptures original notation and a differently notated version *present in the source being transcribed*.
Critical apparatus component declarations.
lemContains the lemma, or base text, of a textual variation.
rdgContains a single reading within a textual variation.
Editorial and transcriptional component declarations.
abbrA generic element for 1) a shortened form of a word, including an acronym or 2) a shorthand notation.
addMarks an addition to the text.
corrContains the correct form of an apparent erroneous passage.
damageContains an area of damage to the physical medium.
delContains information deleted, marked as deleted, or otherwise indicated as superfluous or spurious in the copy text by an author, scribe, annotator, or corrector.
expanContains the expansion of an abbreviation.
origContains material which is marked as following the original, rather than being normalized or corrected.
regContains material which has been regularized or normalized in some sense.
restoreIndicates restoration of material to an earlier state by cancellation of an editorial or authorial marking or instruction.
sicContains apparently incorrect or inaccurate material.
suppliedContains material supplied by the transcriber or editor for any reason.
unclearContains material that cannot be transcribed with certainty because it is illegible or inaudible in the source.
Component declarations that are shared between two or more modules.
staffA group of equidistant horizontal lines on which notes are placed in order to represent pitch or a grouping element for individual 'strands' of notes, rests, etc. that may or may not actually be rendered on staff lines; that is, both diastematic and non-diastematic signs.
May Contain
divLineRepresents a division (divisio) in neume notation. Divisions indicate short, medium, or long pauses similar to breath marks in modern notation.
(MEI.critapp) Groups elements that contain a critical apparatus entry.
appContains one or more alternative encodings.
(MEI.edittrans) Groups elements for editorial interventions that may be useful both in transcribing and in authoring processes.
choiceGroups a number of alternative encodings for the same point in a text.
substGroups transcriptional elements when the combination is to be regarded as a single intervention in the text.
(MEI.edittrans) Groups elements used for editorial transcription of pre-existing source materials.
addMarks an addition to the text.
corrContains the correct form of an apparent erroneous passage.
damageContains an area of damage to the physical medium.
delContains information deleted, marked as deleted, or otherwise indicated as superfluous or spurious in the copy text by an author, scribe, annotator, or corrector.
gapIndicates a point where material has been omitted in a transcription, whether as part of sampling practice or for editorial reasons described in the MEI header.
handShiftMarks the beginning of a passage written in a new hand, or of a change in the scribe, writing style, ink or character of the document hand.
origContains material which is marked as following the original, rather than being normalized or corrected.
regContains material which has been regularized or normalized in some sense.
restoreIndicates restoration of material to an earlier state by cancellation of an editorial or authorial marking or instruction.
sicContains apparently incorrect or inaccurate material.
suppliedContains material supplied by the transcriber or editor for any reason.
unclearContains material that cannot be transcribed with certainty because it is illegible or inaudible in the source.
(MEI.shared) Groups annotation-like elements.
annotProvides a statement explaining the text or indicating the basis for an assertion.
(MEI.shared) Groups notated events that may appear at the layer level in all repertoires.
(MEI.cmn) Groups notated events that may appear at the layer level in CMN.
(MEI.cmn) Groups events that appear in CMN.
bTremA rapid alternation on a single pitch or chord.
beamA container for a series of explicitly beamed events that begins and ends entirely within a measure.
beatRptAn indication that material on a preceding beat should be repeated.
fTremA rapid alternation between a pair of notes (or chords or perhaps between a note and a chord) that are (usually) farther apart than a major second.
graceGrpA container for a sequence of grace notes.
halfmRptA half-measure repeat in any meter.
tupletA group of notes with "irregular" (sometimes called "irrational") rhythmic values, for example, three notes in the time normally occupied by two or nine in the time of five.
(MEI.cmn) Groups events that completely fill a CMN measure.
mRestComplete measure rest in any meter.
mRptAn indication that the previous measure should be repeated.
mRpt2An indication that the previous two measures should be repeated.
mSpaceA measure containing only empty space in any meter.
multiRestMultiple measures of rest compressed into a single symbol, frequently found in performer parts.
multiRptMultiple repeated measures.
(MEI.shared) Groups event elements that occur in all notational repertoires.
barLineVertical line drawn through one or more staves that divides musical notation into metrical units.
chordA simultaneous sounding of two or more notes in the same layer *with the same duration*.
clefIndication of the exact location of a particular note on the staff and, therefore, the other notes as well.
clefGrpA set of simultaneously-occurring clefs.
custosSymbol placed at the end of a line of music to indicate the first note of the next line. Sometimes called a "direct".
noteA single pitched event.
padAn indication of extra visual space between notational elements.
restA non-sounding event found in the source being transcribed.
spaceA placeholder used to fill an incomplete measure, layer, etc. most often so that the combined duration of the events equals the number of beats in the measure.
(MEI.shared) Groups elements that have the same function as a key signature.
keySigWritten key signature.
(MEI.shared) Groups elements that represent a meter signature.
meterSigWritten meter signature.
meterSigGrpUsed to capture alternating, interchanging, mixed or other non-standard meter signatures.
(MEI.shared) Groups notated events at the layer level that are shared by the mensural and neume repertoires.
(MEI.mensural) Groups notated events that may appear at the layer level in the mensural repertoire.
(MEI.mensural) Groups event elements that occur in the mensural repertoire.
dotDot of augmentation or division.
ligatureA mensural notation symbol that combines two or more notes into a single sign.
mensurCollects information about the metrical relationship between a note value and the next smaller value; that is, either triple or duple.
proportDescription of note duration as arithmetic ratio.
(MEI.midi) Groups elements which group MIDI-like elements.
midiContainer for elements that contain information useful when generating MIDI output.
(MEI.neumes) Groups notated events that may appear at the layer level in the neume repertoire.
(MEI.neumes) Groups event elements that occur in the neume repertoire.
divLineRepresents a division (divisio) in neume notation. Divisions indicate short, medium, or long pauses similar to breath marks in modern notation.
neumeSign representing one or more musical pitches.
(MEI.neumes) Groups elements that accommodate neumed text.
syllableNeume notation can be thought of as "neumed text". Therefore, the syllable element provides high-level organization in this repertoire.
(MEI.shared) Groups elements that modify note-like features.
accidRecords a temporary alteration to the pitch of a note.
articAn indication of how to play a note or chord.
dotDot of augmentation or division.
(MEI.shared) Groups milestone-style elements found in music notation.
cbAn empty formatting element that forces text to begin in a new column.
colLayoutAn empty formatting element that signals the start of columnar layout.
sbAn empty formatting element that forces musical notation to begin on a new line.
(MEI.shared) Groups page beginning-like elements.
pbAn empty formatting element that forces text to begin on a new page.
(MEI.usersymbols) Groups elements that function as drawing primitives.
anchoredTextContainer for text that is fixed to a particular page location, regardless of changes made to the layout of the measures around it.
curveA curved line that cannot be represented by a more specific element, such as a slur.
lineA visual line that cannot be represented by a more specific; i.e., semantic, element.
Common Music Notation (CMN) repertoire component declarations.
bTremA rapid alternation on a single pitch or chord.
beamA container for a series of explicitly beamed events that begins and ends entirely within a measure.
beatRptAn indication that material on a preceding beat should be repeated.
fTremA rapid alternation between a pair of notes (or chords or perhaps between a note and a chord) that are (usually) farther apart than a major second.
graceGrpA container for a sequence of grace notes.
halfmRptA half-measure repeat in any meter.
mRestComplete measure rest in any meter.
mRptAn indication that the previous measure should be repeated.
mRpt2An indication that the previous two measures should be repeated.
mSpaceA measure containing only empty space in any meter.
meterSigWritten meter signature.
meterSigGrpUsed to capture alternating, interchanging, mixed or other non-standard meter signatures.
multiRestMultiple measures of rest compressed into a single symbol, frequently found in performer parts.
multiRptMultiple repeated measures.
tupletA group of notes with "irregular" (sometimes called "irrational") rhythmic values, for example, three notes in the time normally occupied by two or nine in the time of five.
Critical apparatus component declarations.
appContains one or more alternative encodings.
Editorial and transcriptional component declarations.
addMarks an addition to the text.
choiceGroups a number of alternative encodings for the same point in a text.
corrContains the correct form of an apparent erroneous passage.
damageContains an area of damage to the physical medium.
delContains information deleted, marked as deleted, or otherwise indicated as superfluous or spurious in the copy text by an author, scribe, annotator, or corrector.
gapIndicates a point where material has been omitted in a transcription, whether as part of sampling practice or for editorial reasons described in the MEI header.
handShiftMarks the beginning of a passage written in a new hand, or of a change in the scribe, writing style, ink or character of the document hand.
origContains material which is marked as following the original, rather than being normalized or corrected.
regContains material which has been regularized or normalized in some sense.
restoreIndicates restoration of material to an earlier state by cancellation of an editorial or authorial marking or instruction.
sicContains apparently incorrect or inaccurate material.
substGroups transcriptional elements when the combination is to be regarded as a single intervention in the text.
suppliedContains material supplied by the transcriber or editor for any reason.
unclearContains material that cannot be transcribed with certainty because it is illegible or inaudible in the source.
Mensural repertoire component declarations.
ligatureA mensural notation symbol that combines two or more notes into a single sign.
mensurCollects information about the metrical relationship between a note value and the next smaller value; that is, either triple or duple.
proportDescription of note duration as arithmetic ratio.
MIDI component declarations.
midiContainer for elements that contain information useful when generating MIDI output.
Neume repertoire component declarations.
divLineRepresents a division (divisio) in neume notation. Divisions indicate short, medium, or long pauses similar to breath marks in modern notation.
divLineRepresents a division (divisio) in neume notation. Divisions indicate short, medium, or long pauses similar to breath marks in modern notation.
neumeSign representing one or more musical pitches.
syllableNeume notation can be thought of as "neumed text". Therefore, the syllable element provides high-level organization in this repertoire.
Component declarations that are shared between two or more modules.
accidRecords a temporary alteration to the pitch of a note.
annotProvides a statement explaining the text or indicating the basis for an assertion.
articAn indication of how to play a note or chord.
barLineVertical line drawn through one or more staves that divides musical notation into metrical units.
cbAn empty formatting element that forces text to begin in a new column.
chordA simultaneous sounding of two or more notes in the same layer *with the same duration*.
clefIndication of the exact location of a particular note on the staff and, therefore, the other notes as well.
clefGrpA set of simultaneously-occurring clefs.
colLayoutAn empty formatting element that signals the start of columnar layout.
custosSymbol placed at the end of a line of music to indicate the first note of the next line. Sometimes called a "direct".
dotDot of augmentation or division.
dotDot of augmentation or division.
keySigWritten key signature.
noteA single pitched event.
padAn indication of extra visual space between notational elements.
pbAn empty formatting element that forces text to begin on a new page.
restA non-sounding event found in the source being transcribed.
sbAn empty formatting element that forces musical notation to begin on a new line.
spaceA placeholder used to fill an incomplete measure, layer, etc. most often so that the combined duration of the events equals the number of beats in the measure.
User-defined symbols component declarations.
anchoredTextContainer for text that is fixed to a particular page location, regardless of changes made to the layout of the measures around it.
curveA curved line that cannot be represented by a more specific element, such as a slur.
lineA visual line that cannot be represented by a more specific; i.e., semantic, element.
Remarks

The term 'layer' is used instead of 'voice' in order to avoid confusion between 'voice' and 'voice leading' and 'voicing'. The def attribute may be used to create a connection with a layerDef element where logical and visual information about the layer is recorded. Alternatively, the n attribute may be used as a reference to a layerDef element with the same value in its n attribute. If neither def nor n attributes are present, then encoding order of the layers is presumed to match the encoding order of the layer definitions.

Declaration
<elementSpec ident="layer" module="MEI.shared">
<desc xml:lang="en">An independent stream of events on a staff.</desc>
<classes>
<memberOf key="att.basic"/>
<memberOf key="att.facsimile"/>
<memberOf key="att.labelled"/>
<memberOf key="att.linking"/>
<memberOf key="att.metadataPointing"/>
<memberOf key="att.nInteger"/>
<memberOf key="att.responsibility"/>
<memberOf key="att.typed"/>
<memberOf key="att.layer.log"/>
<memberOf key="att.layer.vis"/>
<memberOf key="att.layer.ges"/>
<memberOf key="att.layer.anl"/>
<memberOf key="model.layerLike"/>
</classes>
<content>
<rng:zeroOrMore>
<rng:choice>
<rng:ref name="model.annotLike"/>
<rng:ref name="model.appLike"/>
<rng:ref name="model.editLike"/>
<rng:ref name="model.graphicPrimitiveLike"/>
<rng:ref name="model.layerPart"/>
<rng:ref name="model.milestoneLike.music"/>
<rng:ref name="model.transcriptionLike"/>
<rng:ref name="divLine"/>
</rng:choice>
</rng:zeroOrMore>
</content>
<remarks xml:lang="en">
<p>The term 'layer' is used instead of 'voice' in order to avoid confusion between 'voice' and 'voice leading' and 'voicing'. The <att>def</att> attribute may be used to create a connection with a <gi scheme="MEI">layerDef</gi> element where logical and visual information about the layer is recorded. Alternatively, the <att>n</att> attribute may be used as a reference to a <gi scheme="MEI">layerDef</gi> element with the same value in its <att>n</att> attribute. If neither <att>def</att> nor <att>n</att> attributes are present, then encoding order of the layers is presumed to match the encoding order of the layer definitions.</p>
</remarks>
</elementSpec>