Units

BODC (British Oceanographic Data Centre) Units

graybeal — Thu, 07 Sep 2006 23:40:00 -0700

The British Oceanographic Data Centre has been developing parameter and unit lists for an extended period, for many data holdings. They are actively managing their parameter dictionaries as they participate in or lead numerous oceanographic data management projects.

Live access to the BODC units table and many other controlled parameter lists is now available via the BODC Vocabulary Server Web Service.

EPIC (NOAA, PMEL) Units

graybeal — Thu, 18 May 2006 10:01:00 -0700

The EPIC program developed a key file describing all its variables using a numeric code. This code is then encoded into the netCDF file, and includes various attributes for each parameter, including that parameter's units. Thus, the second column of the EPIC key file contains all the units used in the program.

More a working example than an authoritative list of units, but useful to give an idea of the needs of operational programs.

Hydrology Units Ontology

graybeal — Fri, 11 Jan 2008 21:35:00 -0800

These are units used in a hydrologic ontology developed by CUAHSI. They have been encoded (in OWL) using the encoded using the ISO 19103 standard.

International Scientific Units (NIST)

graybeal — Tue, 27 Nov 2007 12:14:00 -0800

NIST has a very coherent description of the model used for working with science units, along with a comprehensive list of abbreviatinos.

A very mature and well described system.

ISO Units Standards

graybeal — Thu, 18 May 2006 09:57:00 -0700

ISO has published several standards on quantities and units, most notably ISO 31 ("Quantities and Units"), which has 14 parts, and ISO 1000, which is the ISO representation of the SI units system.

A very formal and stable standard.

See UCUM units references for a possibly useful perspective on this standard.

MODIS Units

graybeal — Thu, 13 Sep 2007 08:11:00 -0700

These pages have data items for NASA's MODIS satellite, including the units in which each data item is stored. More than a comprehensive list, this is an example.

SWEET Units Ontology

graybeal — Fri, 11 Jan 2008 21:32:00 -0800

Beyond being a simple list of units, this ontology shows the relationship between the different terms, including both how they are built semantically from their parts, and possible numeric relationships.

The ontology is likely to evolve to include more unit terms as needed.

You will need to view this ontology with an ontology editing tool such as Protege or SWOOP. The information is contained in XML, so you can see it in your browser (or by using "View Source" in the Safari browser).

Unidata UDUNITS Units

graybeal — Tue, 27 Nov 2007 12:04:00 -0800

UDUNITS is a library that supports conversion of unit specifications between formatted and binary forms, arithmetic manipulation of unit specifications, and conversion of values between compatible scales of measurement. As part of the library, a list of units and their representations has been provided.

UDUNITS is widely used in environmental science software packages.

Unified Codes for Units of Measure (UCUM)

graybeal — Tue, 27 Nov 2007 12:14:00 -0800

This standard is becoming recommended practice for various organizations, for example some of the OGC standards.

The links provide the following:

Units by Petroleum Open Standards Consortium (POSC)

graybeal — Tue, 27 Nov 2007 12:14:00 -0800

This is a comprehensive approach to defining units of measure for computation, sponsored by the Petroleum Open Standards Consortium. References on the site describe the problem to be solved, the approach taken, and provide the standard and a standard list of units.

Appears to be used in multiple applications.

Perceptive on certain issues that other standards may not be aware of.