Converts Conductance Units

For plant physiologists, converts conductance (e.g. stomatal conductance) to different units: m/s, mol/m^2/s, and umol/m^2/s/Pa.

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In plant physiology, conductance to heat, carbon dioxide, and water vapour are expressed in different units for different purposes. For heat exchange, units of m/s are most often used, whereas for gas exchange units of either mol/m^2/s (the default output from LICOR devices) or umol/m^2/s/Pa are used. I found it difficult to keep all the conversions straight, so I made a small package to help ensure proper conversion.


You can install the current version of gunit from GitHub with:


Or the released version of gunit from CRAN with:



This is a basic example which shows you how to solve convert conductance units:

#> udunits system database from /Library/Frameworks/R.framework/Versions/3.6/Resources/library/units/share/udunits
g_sw <- set_units(0.4, mol/m^2/s)
#> # A tibble: 1 x 3
#>         `m/s` `umol/m^2/s/Pa` `mol/m^2/s`
#>         [m/s] [umol/m^2/Pa/s] [mol/m^2/s]
#> 1 0.009786197        3.947709         0.4
# Change Temperature and Pressure
g_sw <- set_units(0.4, mol/m^2/s)
                    P = set_units(80, kPa), 
                    Temp = set_units(293, K))
#> # A tibble: 1 x 3
#>        `m/s` `umol/m^2/s/Pa` `mol/m^2/s`
#>        [m/s] [umol/m^2/Pa/s] [mol/m^2/s]
#> 1 0.01218068               5         0.4
# Calculations can also be vectorized
g_sw <- set_units(seq(0.1, 0.4, 0.1), mol/m^2/s)
#> # A tibble: 4 x 3
#>         `m/s` `umol/m^2/s/Pa` `mol/m^2/s`
#>         [m/s] [umol/m^2/Pa/s] [mol/m^2/s]
#> 1 0.002446549       0.9869272         0.1
#> 2 0.004893099       1.9738543         0.2
#> 3 0.007339648       2.9607815         0.3
#> 4 0.009786197       3.9477087         0.4


Comments and contributions

I welcome comments, criticisms, and especially contributions! GitHub issues are the preferred way to report bugs, ask questions, or request new features. You can submit issues here:


  • Please report any issues or bugs.
  • License: MIT
  • Get citation information for gunit in R doing citation(package = 'gunit')
  • Please note that the ‘gunit’ project is released with a Contributor Code of Conduct. By contributing to this project, you agree to abide by its terms.


Reference manual

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1.0.0 by Chris Muir, a year ago

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Browse source code at

Authors: Chris Muir [aut, cre]

Documentation:   PDF Manual  

MIT + file LICENSE license

Imports magrittr, stringr, units, tibble

Suggests testthat

Imported by photosynthesis.

See at CRAN