Q392. My XML editor is showing an error on the namespace declaration. How do I resolve it?
A392. The purpose of an XML namespace is to ensure that data elements and attributes referenced in your XML document are uniquely named. This is especially important when your GHG data is combined with data from other programs having data elements with the same name. For example, the XML schemas for Emissions Inventory System (EIS) and e-GGRT each contain a data element named "FacilitySiteIdentifier". This data element serves different purposes depending on the program with which it is associated. Now suppose both systems contain a FacilitySiteIdentifier = 87675. In EIS, that identifier might refer to ABC Acme, Inc. but in e-GGRT, it might refer to the Blue Glass Corporation, a completely different company. Using a namespace identifier avoids such ambiguities. Namespace identifiers are typically three-letter acronyms that precede every data element and attribute tag in your XML. For example, <FacilitySiteIdentifier> becomes <ghg:FacilitySiteIdentifier>. In this example, the first data element name is not unique but it becomes unique when the prefix (ghg:) is added. Namespace identifiers are defined in the declaration statement at the top of each XML file. The declaration statement also contains a reference to the location of the schema definition files. The e-GGRT schema is located at http://www.ccdsupport.com/confluence/display/help/XML+Reporting+Instructions. Alternatively, you may reference a local copy of the schema files within the declaration statement. See the Subpart A XML reporting instructions for more details.