URN

"The functional requirements for Uniform Resource Names were described in 1994 by RFC 1737,^[1] and the syntax was defined in 1997 in RFC 2141^[2]. In these standards, URNs were conceived to be part of a three-part information architecture for the Internet, along with Uniform Resource Locators (URLs) and Uniform Resource Characteristics (URCs), a metadata framework. URNs were distinguished from URLs, which identify resources by specifying their locations in the context of a particular access protocol, such as HTTP or FTP. In contrast, URNs were conceived as persistent, usually opaque or at least location-independent, identifiers assigned within defined namespaces, typically by an authority responsible for the namespace, so that they are globally unique and persistent over long periods of time, even after the resource which they identify ceases to exist or becomes unavailable.

Use of the terms "Uniform Resource Name" and "Uniform Resource Locator" has been deprecated in technical standards in favor of the term Uniform Resource Identifier (URI), which encompasses both.   A URI is a string of characters used to identify or name a resource. URIs are used in many Internet protocols to refer to and access information resources. URI schemes include the familiar http, as well as hundreds of others.  In the "contemporary view", as it is called, all URIs identify or name resources, perhaps uniquely and persistently, with some of them also being "locators" which are resolvable in conjunction with a specified protocol to a representation of the resources.

Other URIs are not locators and are not necessarily resolvable within the bounds of the systems where they are found. These URIs may serve as names or identifiers of resources. Since resources can move, opaque identifiers which are not locators and are not bound to particular locations are arguably more likely than identifiers which are locators to remain unique and persistent over time. But whether a URI is resolvable depends on many operational and practical details, irrespective of whether it is called a "name" or a "locator". In the contemporary view, there is no bright line between "names" and "locators". In accord with this way of thinking, the distinction between Uniform Resource Names and Uniform Resource Locators is now no longer used in formal Internet Engineering Task Force technical standards, though the latter term, URL, is still in wide informal use.

The term "URN" continues now as one of more than a hundred URI "schemes", urn:, paralleling http:, ftp:, and so forth. URIs of the urn: scheme are not necessarily locators; are not required to be associated with a particular protocol or access method; and need not be resolvable. They should be assigned by a procedure which provides some assurance that they will remain unique and identify the same resource persistently over a prolonged period. Some namespaces under the urn: scheme, such as urn:uuid: assign identifiers in a manner which does not require a registration authority, but most of them do. A typical URN namespace is urn:isbn, for International Standard Book Numbers."

https://en.wikipedia.org/wiki/Uniform_Resource_Name

IOOS Observing Asset Identifiers

An IOOS identifier is Uniform Resource Identifier (URI). URIs are commonly used as identifiers in the Internet’s information architecture; an introductory description of URIs may be found on Wikipedia. In fact, IOOS identifiers are based on a specific form of URI, which is called a Uniform Resource Name (URN), which was designed for the identification of resources in particular namespaces. The URN syntax is described in the Internet Engineering Task Force (IETF) Request for Comments (RFC) 2141; the definitions and restrictions established by the RFC 2141 determine the syntactic structure of the IOOS identifiers.

All URIs assigned by IOOS begin with the string urn:ioos:, followed by one or more fields also separated by colons (:). The initial urn: indicates that the URI is indeed a URN. The following ioos: indicates that the URN is in the IOOS namespace.   The ioos namespace has not been formally registered with IANA; therefore, it is rather informal, community-wide namespace.

The additional fields may only include letters and numbers (A-Z, a-z, 0-9) and the following characters: _( ) + , - . = @ ; $ _ ! *_ . Special characters not in the foregoing list must be represented using hexadecimal encoding as %xx, where xx represents a two-digit hex value. The use of such characters in IOOS URNs is not recommended.

http://ioos.github.io/conventions-for-observing-asset-identifiers/ioos_assets_v1.0/

http://ioos.github.io/conventions-for-observing-asset-identifiers/

http://ioos.github.io/


assetid

An ocean data asset ID parser developed and used by Axiom Data Science.

https://github.com/axiom-data-science/assetid