# 4 The root element: <eml:eml>

This element is the root element in all EML documents. The XPath notation is: /eml:eml

The root element holds two important parts, both of which are optional, but recommended.

## 4.1 @schemaLocation (XML attribute)

This attribute is this location (XPath):
/eml:eml/@schemaLocation

The schemaLocation attribute tells a processor the name of the schema to which the EML document belongs and where to find it. Most repositories check schema compliance when data packages are deposited, but it is highly recommended that data managers know how and where to specify the schema that their metadata document should adhere to. This way, they can validate their own work in progress, e.g., through an XML editor like OxygenXML.

## 4.2 @packageId (XML attribute)

This attribute is found at this location (XPath):
/eml:eml/@packageId

As outlined elsewhere, EML preparers should manage unique identifiers and versioning at the local level (see @system discussion below). The packageId attribute can be used to contain the same identifier as is used by the repository.

Context Note: The packageID attribute is required in all EML documents submitted to the EDI repository. It is entered into the repository software, and theformat is standardized to three parts: scope, package-number, revision. The scope should be “edi” unless another scope is justified by prior arrangement. See Example 1.

Example 1: attributes packageId, id, system, and scope

<?xml version="1.0" encoding="UTF-8"?>
<eml:eml xmlns:ds="eml://ecoinformatics.org/dataset-2.1.0"
xmlns:xs="http://www.w3.org/2001/XMLSchema"
xmlns:eml="eml://ecoinformatics.org/eml-2.1.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:stmml="http://www.xml-cml.org/schema/stmml"
xsi:schemaLocation="eml://ecoinformatics.org/eml-2.1.0
https://nis.lternet.edu/eml-2.1.0/eml.xsd"
packageId="knb-lter-fls.21.3"
system="FLS"
scope="system">