URLs for Accessing Data

Christopher Reedy Christopher.Reedy at noaa.gov
Thu Nov 15 12:52:09 EST 2001

Here is some guidance for how URLs should be handled in metadata. Please
let me know if this causes any problems.



The FGDC standard provides two tags that can be used for URLs for the
data described by a given metadata record. These are:

  8.10 Online Linkage - under 1.1 Citation, and Network Resource Name

The FGDC standard, in the FAQs, states: 

FAQ: What is a Network Resource Name?

A: The name of the data set on the network. When appropriate, Uniform
Resource Locators (URL) should be provided.

FAQ: What is the difference between the Network Resource Name and the
Online Linkage (8.10) data element?

A: The Network Resource Name is the name of the file or service from
which the data set can be obtained from a distributor. Different
distributors that provide online access to a data set probably would do
so from different sites. The Online Linkage is the name of the file or
service maintained by the originator (when used with "Citation" (1.1))
or the name of the file or service from which the data set was obtained
(when used with "Source Citation" (

(end of FAQ)

For CoRIS both the Online Linkage and the Network Resource Name can be
used to define the location of the data. Wherever possible, the URL
where the data can be obtained should be found in the Network Resource
Name. As described in the FAQ, the Online Linkage should be the location
of the data as provided by the originator, and the Network Resource Name
should be used for the location where the data can currently be
obtained. For example, if the data is copied from its original location
to an archive, the Online Linkage should contain the original location
and the Network Resource Name should contain the location in the

In general, both Online Linkage and Network Resource Name should be
URLs. Information about other textual information regarding ways to
obtain the data can be place in, Access Instructions.

As part of data discovery, the CoRIS software will provide access to all
the URLs found in under both the Online Linkage and the Network Resource
Name tags. The URLs will be ordered with Network Resource Name URLs
first, followed by Online Linkage URLs.

This is informal and not an official Mitretek Systems position.
Dr. Christopher L. Reedy, Senior Principal Software Engineer
Mitretek Systems M/S Z551, 7525 Colshire Drive, McLean, VA 22102-7400
Email: creedy at mitretek.org  Phone: (703) 610-1615  FAX: (703) 610-1603

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