This archive contains answers to questions sent to Unidata support through mid-2025. Note that the archive is no longer being updated. We provide the archive for reference; many of the answers presented here remain technically correct, even if somewhat outdated. For the most up-to-date information on the use of NSF Unidata software and data services, please consult the Software Documentation first.
Nan, > Will there be a viewable page for udunits v2 which we can use to > search for units without needing to download the whole package? > There's a very useful page like that for v1, at > http://www.unidata.ucar.edu/software/udunits/udunits-1/etc/udunits.dat > and very nice to be able to search for terms with a browser. Good idea. I'll see what I can do. In the meantime, I've attached the files that comprise the XML database. > If this page exists for udunits-2, I can't find it. I don't necessarily > need the whole package on every system I work on, but often just > want to check unit names while I'm developing code on a laptop. > > Thanks - Nan Galbraith > > -- > ******************************************************* > * Nan Galbraith (508) 289-2444 * > * Upper Ocean Processes Group Mail Stop 29 * > * Woods Hole Oceanographic Institution * > * Woods Hole, MA 02543 * > ******************************************************* Regards, Steve Emmerson Ticket Details =================== Ticket ID: KMJ-592371 Department: Support UDUNITS Priority: Normal Status: Open
<?xml version="1.0" encoding="US-ASCII"?> <!-- Copyright 2008, 2009 University Corporation for Atmospheric Research This file is part of the UDUNITS-2 package. See the file LICENSE in the top-level source-directory of the package for copying and redistribution conditions. --> <unit-system> <import>udunits2-prefixes.xml</import> <import>udunits2-base.xml</import> <import>udunits2-derived.xml</import> <import>udunits2-accepted.xml</import> <import>udunits2-common.xml</import> </unit-system>
<?xml version="1.0" encoding="US-ASCII"?> <!-- Copyright 2008, 2009 University Corporation for Atmospheric Research This file is part of the UDUNITS-2 package. See the file LICENSE in the top-level source-directory of the package for copying and redistribution conditions. SI prefixes --> <unit-system> <prefix> <value>1e24</value> <name>yotta</name> <symbol>Y</symbol> </prefix> <prefix> <value>1e21</value> <name>zetta</name> <symbol>Z</symbol> </prefix> <prefix> <value>1e18</value> <name>exa</name> <symbol>E</symbol> </prefix> <prefix> <value>1e15</value> <name>peta</name> <symbol>P</symbol> </prefix> <prefix> <value>1e12</value> <name>tera</name> <symbol>T</symbol> </prefix> <prefix> <value>1e9</value> <name>giga</name> <symbol>G</symbol> </prefix> <prefix> <value>1e6</value> <name>mega</name> <symbol>M</symbol> </prefix> <prefix> <value>1e3</value> <name>kilo</name> <symbol>k</symbol> </prefix> <prefix> <value>100</value> <name>hecto</name> <symbol>h</symbol> </prefix> <prefix> <value>10</value> <name>deka</name> <symbol>da</symbol> </prefix> <prefix> <value>.1</value> <name>deci</name> <symbol>d</symbol> </prefix> <prefix> <value>.01</value> <name>centi</name> <symbol>c</symbol> </prefix> <prefix> <value>1e-3</value> <name>milli</name> <symbol>m</symbol> </prefix> <prefix> <value>1e-6</value> <name>micro</name> <symbol>µ</symbol> <!-- MICRO SIGN --> <symbol>μ</symbol> <!-- Greek small letter "mu" --> </prefix> <prefix> <value>1e-9</value> <name>nano</name> <symbol>n</symbol> </prefix> <prefix> <value>1e-12</value> <name>pico</name> <symbol>p</symbol> </prefix> <prefix> <value>1e-15</value> <name>femto</name> <symbol>f</symbol> </prefix> <prefix> <value>1e-18</value> <name>atto</name> <symbol>a</symbol> </prefix> <prefix> <value>1e-21</value> <name>zepto</name> <symbol>z</symbol> </prefix> <prefix> <value>1e-24</value> <name>yocto</name> <symbol>y</symbol> </prefix> </unit-system>
<?xml version="1.0" encoding="US-ASCII"?> <!-- Copyright 2008, 2009 University Corporation for Atmospheric Research This file is part of the UDUNITS-2 package. See the file LICENSE in the top-level source-directory of the package for copying and redistribution conditions. SI base units. --> <unit-system> <unit> <!-- The meter is the length of the path travelled by light in vacuum during a time interval of 1/299 792 458 of a second. --> <base/> <name><singular>meter</singular></name> <symbol>m</symbol> <aliases> <name><singular>metre</singular></name> </aliases> </unit> <unit> <!-- The kilogram is the unit of mass; it is equal to the mass of the international prototype of the kilogram. --> <base/> <name><singular>kilogram</singular></name> <symbol>kg</symbol> </unit> <unit> <!-- The second is the duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium 133 atom. --> <base/> <name><singular>second</singular></name> <symbol>s</symbol> </unit> <unit> <!-- The ampere is that constant current which, if maintained in two straight parallel conductors of infinite length, of negligible circular cross-section, and placed 1 meter apart in vacuum, would produce between these conductors a force equal to 2e-7 newton per meter of length. --> <base/> <name><singular>ampere</singular></name> <symbol>A</symbol> </unit> <unit> <!-- The kelvin, unit of thermodynamic temperature, is the fraction 1/273.16 of the thermodynamic temperature of the triple point of water. --> <base/> <name><singular>kelvin</singular></name> <symbol>K</symbol> </unit> <unit> <!-- 1. The mole is the amount of substance of a system which contains as many elementary entities as there are atoms in 0.012 kilogram of carbon 12. 2. When the mole is used, the elementary entities must be specified and may be atoms, molecules, ions, electrons, other particles, or specified groups of such particles. --> <base/> <name><singular>mole</singular></name> <symbol>mol</symbol> </unit> <unit> <!-- The candela is the luminous intensity, in a given direction, of a source that emits monochromatic radiation of frequency 540e12 hertz and that has a radiant intensity in that direction of 1/683 watt per steradian. --> <base/> <name><singular>candela</singular></name> <symbol>cd</symbol> </unit> </unit-system>
<?xml version="1.0" encoding="US-ASCII"?> <!-- Copyright 2008, 2009 University Corporation for Atmospheric Research This file is part of the UDUNITS-2 package. See the file LICENSE in the top-level source-directory of the package for copying and redistribution conditions. SI derived units with special names and symbols --> <unit-system> <unit> <dimensionless/> <name><singular>radian</singular></name> <symbol>rad</symbol> </unit> <unit> <def>rad^2</def> <name><singular>steradian</singular></name> <symbol>sr</symbol> </unit> <unit> <def>1/s</def> <name><singular>hertz</singular></name> <symbol>Hz</symbol> </unit> <unit> <def>1e-3 kg</def> <name><singular>gram</singular></name> <symbol>g</symbol> </unit> <unit> <def>m.kg/s^2</def> <name><singular>newton</singular></name> <symbol>N</symbol> </unit> <unit> <def>N/m^2</def> <name><singular>pascal</singular></name> <symbol>Pa</symbol> </unit> <unit> <def>N.m</def> <name><singular>joule</singular></name> <symbol>J</symbol> </unit> <unit> <def>J/s</def> <name><singular>watt</singular></name> <symbol>W</symbol> </unit> <unit> <def>s.A</def> <name><singular>coulomb</singular></name> <symbol>C</symbol> </unit> <unit> <def>W/A</def> <name><singular>volt</singular></name> <symbol>V</symbol> </unit> <unit> <def>C/V</def> <name><singular>farad</singular></name> <symbol>F</symbol> </unit> <unit> <def>V/A</def> <name><singular>ohm</singular></name> <symbol>Ω</symbol> <!-- Greek capital letter omega (preferred) --> <aliases> <symbol>Ω</symbol> <!-- OHM SIGN --> </aliases> </unit> <unit> <def>A/V</def> <name> <singular>siemens</singular> </name> <symbol>S</symbol> </unit> <unit> <def>V.s</def> <name><singular>weber</singular></name> <symbol>Wb</symbol> </unit> <unit> <def>Wb/m^2</def> <name><singular>tesla</singular></name> <symbol>T</symbol> </unit> <unit> <def>Wb/A</def> <name><singular>henry</singular></name> <symbol>H</symbol> </unit> <unit> <def>K @ 273.15</def> <name> <singular>degree_Celsius</singular> <plural>degrees_Celsius</plural> </name> <symbol>°C</symbol> <!-- DEGREE SIGN --> </unit> <unit> <def>cd.sr</def> <name><singular>lumen</singular></name> <symbol>lm</symbol> </unit> <unit> <def>lm/m^2</def> <name><singular>lux</singular></name> <symbol>lx</symbol> </unit> <unit> <def>mol/s</def> <name><singular>katal</singular></name> <symbol>kat</symbol> </unit> <!-- SI derived units with special names and symbols admitted for reasons of safeguarding human health --> <unit> <def>1/s</def> <aliases> <!-- The following are aliases because "1/s" is already mapped to "hertz" and "Hz" --> <name><singular>becquerel</singular></name> <symbol>Bq</symbol> </aliases> </unit> <unit> <def>J/kg</def> <name><singular>gray</singular></name> <symbol>Gy</symbol> </unit> <unit> <def>J/kg</def> <aliases> <name><singular>sievert</singular></name> <symbol>Sv</symbol> </aliases> </unit> </unit-system>