FAIRsharing record for: The Unified Code for Units of Measure

This FAIRsharing record describes: The Unified Code for Units of Measure is a code system intended to include all units of measures being contemporarily used in international science, engineering, and business. The purpose is to facilitate unambiguous electronic communication of quantities together with their units. The focus is on electronic communication, as opposed to communication between humans. A typical application of The Unified Code for Units of Measure are electronic data interchange (EDI) protocols, but there is nothing that prevents it from being used in other types of machine communication. How does it relate? The Unified Code for Units of Measure is inspired by and heavily based on ISO 2955-1983, ANSI X3.50-1986, and HL7's extensions called ISO+. The respective ISO and ANSI standards are both entitled Representation of [...] units in systems with limited character sets where ISO 2955 refers to SI and other units provided by ISO 1000-1981, while ANSI X3.50 extends ISO 2955 to include U.S. customary units. Because these standards carry the restriction of limited character sets in their names they seem to be of less value today where graphical user interface and laser printers are in wide-spread use, which is why the european standard ENV 12435 in its clause 7.3 declares ISO 2955 obsolete. ENV 12435 is dedicated exclusively to the communication of measurements between humans in display and print, and does not provide codes that can be used in communication between systems. It does not even provide a specification that would allow communication of units from one system to the screen or printer of another system. The issue about displaying units in the common style defined by the 9th Conf?rence G?n?rale des Poids et Mesures (CGPM) in 1947 is not just the character set. Although The Unicode Standard and its predecessor ISO/IEC 10646 is the richest character set ever it is still not enough to specify the presentation of units because there are important typographical details such as superscripts, subscripts, roman and italics.

本FAIRsharing记录描述如下：统一计量单位代码（Unified Code for Units of Measure）是一套旨在涵盖当前国际科学、工程与商业领域同步使用的全部计量单位的代码体系。其核心目标是实现带有计量单位的物理量的无歧义电子通信，且聚焦于机器间的电子通信，而非人类之间的交互。统一计量单位代码的典型应用为电子数据交换（EDI）协议，但该代码体系并无使用限制，亦可应用于其他类型的机器通信场景。
该代码体系的设计灵感源自并大量基于ISO 2955-1983、ANSI X3.50-1986以及HL7推出的名为ISO+的扩展规范。上述ISO与ANSI标准的全称均为《有限字符集系统中的单位表示》，其中ISO 2955参考了国际单位制（SI）单位及ISO 1000-1981规定的其他单位，而ANSI X3.50则在ISO 2955的基础上扩展纳入了美制惯用单位。由于这些标准的名称中带有“有限字符集”的限制条件，在图形用户界面与激光打印机已广泛普及的当下，其应用价值已大幅降低——这也是欧洲标准ENV 12435在其第7.3条款中宣布ISO 2955作废的原因。ENV 12435仅专注于人类通过显示与打印方式进行的测量值通信，并未提供可用于系统间通信的单位代码，甚至未制定可实现从一个系统向另一系统的屏幕或打印机传输单位信息的规范。
1947年第9届国际计量大会（Conférence Générale des Poids et Mesures，CGPM）所定义的标准单位显示格式，其呈现问题并非仅由字符集限制导致。尽管《Unicode标准》及其前身ISO/IEC 10646是目前最丰富的字符集，但仍不足以完整规范单位的呈现形式，因为还涉及上标、下标、正体与斜体等重要排版细节。