CIESIN's Guide to FGDC Compliant Metadata

Introduction to the FGDC Elements

The Elements

The FGDC Content Standard is a collection of 334 hierarchically organized elements that define the content of the metadata record. These elements fall into one of two categories - data elements or compound elements. Data elements are those that can be assigned a value, while compound elements cannot be assigned a value and exist only to contain other elements. They simply describe the relationship among other elements giving an overall structure to the standard. Of the 334 elements, 215 are data elements, and the remaining 119 elements are compound elements.

The elements are organized hierarchically, with the starting point of "metadata" (section 0). "Metadata" is considered a compound element that is composed of 10 numbered sections, each representing a different concept about the dataset. Sections contain both data elements and compound elements. Compound elements are in turn defined by other compound elements and/or data elements.

The first seven sections of the standard are the Major, or what we refer to as the "Primary" metadata sections. They are:

• Section 1: Identification Information
• Section 2: Data Quality Information
• Section 3: Spatial Data Organization Information
• Section 4: Spatial Reference Information
• Section 5: Entity and Attribute Information
• Section 6: Distribution Information
• Section 7: Metadata Reference Information
  

Of these, only Section 1: Identification Information, and Section 7: Metadata Reference are considered mandatory, and are absolutely required for all records. These mandatory elements are referred to as the "core" elements.

The last three sections are the Minor, or Floating sections. They are used by other sections and never stand alone. They are used in conjunction with metadata elements found throughout sections 1 - 7, and are thus defined once for convenience. They are:

• Section 8: Citation Information
• Section 9: Time Period Information
• Section 10: Contact Information
  

Optionality

Of the 215 elements that can be assigned a value, only a few dozen are considered "mandatory". The remainder are considered "mandatory if applicable", or "optional". The FGDC refers to this as optionality. The optionality of a section or compound element always takes precedence over the elements that it contains. Once a section or compound element is recognized by the dataset producer as applicable, then the optionality of its subordinate elements is to be interpreted.

The standard defines these categories as follows:

• Mandatory elements must be provided. If the information is not known for a mandatory data element, the entry "Unknown" or a similar statement should be given.
• Mandatory-if-applicable elements must be provided if the dataset exhibits the characteristic defined by the element.
• Optional elements are provided at the discretion of the metadata producer. Essentially, they provide a place for information that might otherwise be lost if placed in a general comment field.

We highly recommended the USGS's "Image Map of the Content Standard for Digital Geospatial Metadata" as a complement to this guide. It is a graphical representation of the standard with the elements color coded according to their optionality.

CIESIN's Guide to FGDC Compliant Metadata

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