HED specification

Links

• PDF released version (V3.0.0)

• PDF working version

• Specification source

• Stable specification source

• HED resources

• HED project homepage

The HED specification document formalizes the syntax and behavior of HED (Hierarchical Event Descriptors) vocabulary, annotations, and supporting tools. The specification supports three versions of the specification:

• develop - development branch which is under discussion.

• latest - includes revisions approved by the HED Working Group but not released.

• stable - the latest released form.

For more information about HED see The HED project homepage and the HED resources page.

Contents:

• 1. Introduction to HED
  • 1.1. Scope of HED
  • 1.2. Brief history of HED
  • 1.2. Goals of HED
  • 1.3. HED design principles
  • 1.4. Specification organization
• 2. HED terminology
  • Agent [*]
  • Condition-variable [*]
  • Control-variable [*]
  • Dataset
  • Event [*]
  • Event-context [*]
  • Event marker
  • Event-stream [*]
  • Experiment-participant [*]
  • Experimental-trial [*]
  • HED schema [*]
  • HED string
  • HED tag
  • Indicator-variable [*]
  • Parameter [*]
  • Recording [*]
  • Tag-group
  • Task [*]
  • Temporal scope
  • Time-block [*]
• 3. HED formats
  • 3.1. HED schema format
    • 3.1.1. Official schema releases
    • 3.1.2. Schema layout overview
      • 3.1.2.1. The header
      • 3.1.2.2. The prologue
      • 3.1.2.3. The schema section
      • 3.1.2.4. Unit classes and units
      • 3.1.2.5. Unit modifiers
      • 3.1.2.6. Value classes
      • 3.1.2.7. Schema attributes
      • 3.1.2.8. Schema properties
      • 3.1.2.9. The epilogue
    • 3.1.3. Naming conventions
      • 3.1.3.1. Node elements
      • 3.1.3.2. Epilogue and prologue
      • 3.1.3.3. Naming in other blocks
    • 3.1.4. Mediawiki schema format
    • 3.1.5. XML schema format
  • 3.2. HED annotation format
    • 3.2.1. Vocabulary organization
    • 3.2.2. Tag forms
    • 3.2.3. Tag case-sensitivity
    • 3.2.4. Tags that take values
    • 3.2.5. Tag extensions
    • 3.2.6. Tag prefixes
    • 3.2.7. Strings and groups
      • 3.2.7.1. Parenthesis and order
      • 3.2.7.2. Tag group attributes
      • 3.2.7.3. Empty tags and groups
      • 3.2.7.4. Repeated expressions
    • 3.2.8. Special tags
      • 3.2.8.1. The Definition tag
      • 3.2.8.2. Def and Def-expand tags
      • 3.2.8.3. Onset and Offset tags
      • 3.2.8.4. The Event-context tag
    • 3.2.9. Sidecars
      • 3.2.9.1. Sidecar entries
      • 3.2.9.2. Sidecar validation
    • 3.2.10. Tabular files
      • 3.2.10.1. Tabular annotations
      • 3.2.10.2. Event-level processing
      • 3.2.10.3 File-level processing
• 4. Basic annotation
  • 4.1. Instantaneous events
  • 4.2. Sensory presentations
  • 4.3. Task role
  • 4.4. Agent actions
  • 4.5. Experimental control
  • 4.6. Data features
  • 4.7. What else?
• 5. Advanced annotation
  • 5.1. Creating definitions
  • 5.2. Using definitions
    • 5.2.1. The Def tag
    • 5.2.2. The Def-expand tag
  • 5.3. Temporal scope
    • 5.3.1. Using Onset and Offset
    • 5.3.2. Using Duration
    • 5.3.3. Using Delay
  • 5.4. Event streams
  • 5.5. Event contexts
  • 5.6. Experimental design
  • 5.7. Specialized annotation
    • 5.7.1. Parameter tags
• 6. Infrastructure and tools
  • 6.1. Basic tag handling
    • 6.1.1. Tag forms
    • 6.1.2. Parentheses and commas
    • 6.1.3. Tag ordering
    • 6.1.4. Definitions
  • 6.2. File-level handling
  • 6.3. HED support of BIDS
    • 6.3.1. BIDS tabular files
    • 6.3.2. BIDS sidecars
    • 6.3.3. Annotation assembly
    • 6.3.4. HED version in BIDS
    • 6.3.5. HED in the BIDS validator
    • 6.3.5. HED python tools
• 7. Library schema
  • 7.1. Defining a schema
  • 7.2. Schema namespaces
  • 7.3. Library schema layout
    • 7.3.1. Required sections
    • 7.3.2. Relation to standard HED schema
    • 7.3.3. Schema properties
    • 7.3.4. Unit classes
    • 7.3.5. Value classes
    • 7.3.6. Schema attributes
    • 7.3.7. Syntax checking
  • 7.4. Library schemas in BIDS
    • 7.1. Using library schema in BIDS
• A. Schema format details
  • A.1. Auxiliary schema sections
    • A.1.1. Unit classes and units
    • A.1.2. Unit modifiers
    • A.1.3. Value classes
    • A.1.4. Schema attributes
    • A.1.5. Schema properties
  • A.2. Mediawiki file format
    • A.2.1. Overall file layout
    • A.2.2. The header-line
    • A.2.3. The prologue and epilogue
    • A.2.4. Schema sections
    • A.2.5. Auxiliary sections
      • A.2.5.1. Unit classes and units
      • A.2.5.2. Unit modifiers
      • A.2.5.3. Value classes
      • A.2.5.4. Schema attributes
      • A.2.5.5. Schema properties
  • A.3. XML file format
    • A.3.1. Overall file layout
    • A.3.2. The header
    • A.3.3. The prologue and epilogue
    • A.3.4. The schema section
    • A.3.5. Auxiliary sections
      • A.3.5.1. Unit classes
      • A.3.5.2. Unit modifiers
      • A.3.5.3 Value classes
      • A.3.5.4. Schema attributes
      • A.3.5.5. Schema properties
• B. HED errors
  • B.1. HED validation errors
    • CHARACTER_INVALID
    • COMMA_MISSING
    • DEF_EXPAND_INVALID
    • DEF_INVALID
    • DEFINITION_INVALID
    • NODE_NAME_EMPTY
    • ONSET_OFFSET_ERROR
    • PARENTHESES_MISMATCH
    • PLACEHOLDER_INVALID
    • REQUIRED_TAG_MISSING
    • SIDECAR_INVALID
    • SIDECAR_KEY_MISSING*
    • STYLE_WARNING*
    • TAG_EMPTY
    • TAG_EXPRESSION_REPEATED
    • TAG_EXTENDED*
    • TAG_EXTENSION_INVALID
    • TAG_GROUP_ERROR
    • TAG_INVALID
    • TAG_NOT_UNIQUE
    • TAG_PREFIX_INVALID
    • TAG_REQUIRES_CHILD
    • TILDES_UNSUPPORTED
    • UNITS_INVALID
    • UNITS_MISSING*
    • VALUE_INVALID
    • VERSION_DEPRECATED*
  • B.2. Schema validation errors
    • B.2.1. General validation errors
      • LIBRARY_NAME_INVALID
      • SCHEMA_ATTRIBUTE_INVALID
      • SCHEMA_CHARACTER_INVALID
      • SCHEMA_DUPLICATE_NODE
      • SCHEMA_HEADER_INVALID
      • SCHEMA_SECTION_MISSING
      • SCHEMA_VERSION_INVALID
    • B.2.2. Mediawiki format errors
      • WIKI_DELIMITERS_INVALID
      • WIKI_LINE_START_INVALID
      • WIKI_SEPARATOR_INVALID
    • B.2.3. XML format errors
      • XML_SYNTAX_INVALID
    • B.2.4 Schema loading errors

Indices and tables

• Index

• Module Index

• Search Page