The "eml" element allows for the inclusion of any metadata content in a single EML document. In general, dataset resources, literature resources, and software resources, or another type that extends eml-resource are described using an eml document. The eml document represents a "package" that can contain both metadata and data. It can optionally include non-EML metadata through the flexibility of the "additionalMetadata" element. Any additional metadata that is provided can provide a pointer into the EML metadata indicating what the context of the additional metadata is (i.e., what it describes). For example, a spatial raster image might be described in EML, and an FGDC CSDGM metadata document could be included in the additionalMetadata element with a pointer to the EML spatialRaster element to indicate that the FGDC metadata is providing supplemental documentation about that particular image entity. There is no validity constraint that restricts what metadata may be present in additionalMetadata.

An optional access tree at this location controls access to the entire metadata document. If this access element is omitted from the document, then the package submitter should be given full access to the package but all other users should be denied all access.

A resource that describes a data set, which can include one or more data entities such as data tables and spatial images (raster and vector). If included, this represents the primary resource that is described in this eml document.

A resource that describes a literature citation that one might find in a bibliography. If included, this represents the primary resource that is described in this eml document.

A resource that describes a software package, which can include commercial and non-commercial software as well as data processing programs. If included, this represents the primary resource that is described in this eml document.

A resource that describes a scientific protocol, which can include one or more descriptions of methods and procedures. If included, this represents the primary resource that is described in this eml document.

A flexible field for including any other relevant metadata that pertains to the resource being described. This field allows EML to be extensible in that any XML-based metadata can be included in this element, including metadata from other standards such as the FGDC CSDGM. The "describes" element of this field allows the specific part of the resource which is described by the additional metadata to be indicated formally.

A pointer to the id attribute for the sub-portion of the resource that is described by this additional metadata. This is a formal field in that it is an error to provide a value in the "describes" element that does not correspond to the value of one of the "id" attributes in another eml module. This is designed to allow automated processors to discover the contextual relationship between the additional metadata and the resource it describes.
Example(s):
knb.343.22

This element contains the additional metadata to be included in the document. This element should be used for extending EML to include metadata that is not already available in another part of the EML specification, or to include site- or system-specific extensions that are needed beyond the core metadata. The additional metadata contained in this field describes the element referenced in the 'describes' element preceding it. The content of this field is any well-formed XML fragment. If that content contains namespace declarations, and if the namespace declaration can be resolved to a schema definition, then the content will be validated against that schema definition. If no namespace is present, or if no schema can be resolved, validation for this fragment will be skipped (validation is "lax").
Example(s):
<embargoDate>2006-10-10</embargoDate>

Type: res:IDType

Use: optional

Type: xs:string

Use: required

A unique identifier for this entire EML metadata document that can be used to reference it elsewhere. This identifier can be interpreted as the formal accession number for this EML package, and is therefore required. It must be unique within a particular data management system (see the "system" attribute).
Example(s):
knb.343.22

Type: res:SystemType

Use: required

Type: res:ScopeType

The scope of the identifier. Scope is generally set to either "system", meaning that it is scoped according to the "system" attribute, or "document" if it is only to be in scope within this single document instance. In this particular use of scope, it is FIXED to be "system" because the packageId is required and always has the scope of the required "system".
Example(s):
system

Use: optional