Description Usage Arguments Value Author(s) References See Also Examples
The function optimises 2-parameter van Genuchten particle size distribution function of Haverkamp & Parlange (1986).
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 | haverkamp(data = NULL, D = NULL, fr = NULL, a = 1, b = 1, p = NULL,
group = NULL)
## Default S3 method:
haverkamp(data = NULL, D = NULL, fr = NULL, a = 1,
b = 1, p = NULL, group = NULL)
## S3 method for class 'haverkamp'
plot(x, main = "Particle Size Distribution Function",
xlab = "Particle Diameter", ylab = "Fraction", ...)
## S3 method for class 'haverkamp'
coef(object, ...)
## S3 method for class 'haverkamp'
predict(object, D, ...)
|
data |
a dataframe of Particle Size Distribution. It can have column names of diameter of the particles "D" [mm], and fraction of the particles "fr" that ranges from 0-1. |
D |
character. The corresponding diameter in the data. |
fr |
character. The corresponding fraction of the particles. |
a |
an initial value of 'a' parameter to be optimised |
b |
an initial value of 'b' parameter to be optimised |
p |
porosity[g/m^3] |
group |
character. The name of the group variables if the data is from different areas. |
x |
a return object of the function. |
main |
Title of the plot |
xlab |
x label of the plot |
ylab |
y label of the plot |
... |
Any other graphical parameter |
object |
Model output object |
PD: predicted fraction by mass of particles passing a particular diameter
sand: percentage of sand
clay: percentage of clay
silt: percentage of silt
a: optimised a parameter
b: optimised b parameter
George Owusu
Haverkamp, R., & Parlange, J. Y. (1986). Predicting the Water-Retention Curve from Particle-Size Distribution:1. Sandy Soils Without Organic Matter. Soil Sc, 142, 325-339.
zhuang3
, zhuang4
,lass3
,logarithmic
,
logistic2
, logistic3
,logistic4
,fredlund3
,
fredlund4
, jaky
,andersson
,gompertz
Other van-Genuchten functions: zhuang3
,
zhuang4
1 2 3 4 5 6 7 8 9 10 |
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