The <Related_URL> field specifies links to Internet sites that contain information related to the data, as well as related Internet sites such as project home pages, related data archives/servers, metadata extensions, online software packages, web mapping services, and calibration/validation data. The <Related_URL> field consists of

<URL_Content_Type> Describes the type of URL being referenced. The <URL_Content_Type> is selected from a list of controlled URL content type keywords and consists of:

<Type> Describes the type resources being referenced by the URL. For example, <Type>GET DATA></Type>
<Subtype> Describes the subtype of the resource being referenced by the URL.

<URL>is the URL to the resource associated with the data set.
<Description> provides information about the resource defined by the <URL>

Syntax

Related_URL>
    <URL_Content_Type>
      <Type>Related URL Type keyword</Type>
      <Subtype>Related URL Subtype keyword</Subtype>
    </URL_Content_Type>
    <URL>URL up to 600 characters</URL>
    <Description>Text</Description>
</Related_URL>

<Description> may contain multiple lines of text. Characters may be selected from the UTF-8 character set.

Usage

The <Related_URL> field is highly recommended and may be repeated.
The <URL_Content_Type> and <URL> fields are required.
The <URL_Content_Type> subfields <Type> and <Subtype> must be selected from the set of URL Content Type keywords. <Subtype> is not required.
The <URL> subfield may be repeated within the <Related_URL>.
The <Description> subfield is recommended and unrepeatable.

Examples

<Related_URL>
    <URL_Content_Type>
    <Type>VIEW PROJECT HOME PAGE </Type>
    </URL_Content_Type>
    <URL>http://www.esipfed.org/</URL>
    <Description>Homepage of the Earth Science Information Partners (ESIP)
    </Description>
</Related_URL>

Example of a <Related_URL> with access to data:
<Related_URL>
   <URL_Content_Type>
<Type> GET DATA </Type>
    <Subtype>GIOVANNI</Subtype>
</URL_Content_Type>
    <URL> ftp://g0dup05u.ecs.nasa.gov/data/Giovanni/MODIS/GOCART/</URL>
    <Description>Access to data files </Description>
</Related_URL>

Example of a <Related_URL> with repeating <URL> subfields.

<Related_URL>
   <URL_Content_Type>
   <Type>GET DATA </Type>
</URL_Content_Type>
   <URL>ftp://ftp.ncdc.noaa.gov/pub/data/paleo/paleocean/by_contributor/medina-elizalde2005/medina-elizalde2005.txt </URL>
   <URL>ftp://ftp.ncdc.noaa.gov/pub/data/paleo/paleocean/by_contributor/medina-elizalde2005/</URL>
   <Description>Access to data and documentation files </Description>
</Related_URL>

Visit GCMD website

This document should be cited as:
Directory Interchange Format (DIF) Writer's Guide, 2008.
Global Change Master Directory. National Aeronautics and Space Administration. [http://gcmd.nasa.gov/User/difguide/].