L1_profiles {aqp}  R Documentation 
The L1 estimator, or geometric median, is a multivariate generalization of the (univariate) median concept. This function performs a multivariate aggregation (via L1 estimator) according to a suite of ratioscale soil properties. The L1 estimator is applied to soil profile data that have been sliced to a 1depthunit basis.
See the L1 Profiles Tutorial for additional examples.
L1_profiles( x, fm, basis = 1, method = c("regex", "simple", "constant"), maxDepthRule = c("max", "min"), maxDepthConstant = NULL )
x 

fm 
formula, for example: 
basis 
positive integer, aggregation basis (e.g. 1 for 1depthunit intervals). Values other than 1 are not currently supported. 
method 
soil depth evaluation method: "regex" for regular expression, "simple", or "constant". See details. 
maxDepthRule 
maximum depth rule: "max" or "min" See details. 
maxDepthConstant 
positive integer, maximum depth when 
See this related tutorial for additional examples. The method
, maxDepthRule
, and maxDepthConstant
arguments set the maximum depth (over the entire collection) of analysis used to build "L1 profiles". The following rules are available:
method = 'regex'
uses pattern matching on horizon designations (note that hzdesgnname
metadata must be set with hzdesgnname(x) < 'columnname'
)
method = 'simple'
uses min
or max
as applied to x
, no accounting for nonsoil horizons (e.g. Cr or R)
method = 'constant'
uses a fixed depth value supplied by maxDepthConstant
The maxDepthRule
argument sets depth calculation constraint, applied to soil depths computed according to method
(min
or max
).
a SoilProfileCollection
object
This function requires the Gmedian
package.
Cardot, H., Cenac, P. and Zitt, PA. (2013). Efficient and fast estimation of the geometric median in Hilbert spaces with an averaged stochastic gradient algorithm. Bernoulli, 19, 1843.