mpspline: Spline discrete soils data - multiple sites

In mpspline2: Mass-Preserving Spline Functions for Soil Data

Spline discrete soils data - multiple sites

Description

This function implements the mass-preserving spline method of Bishop et al (1999) (doi: 10.1016/S0016-7061(99)00003-8) for interpolating between measured soil attributes down a soil profile, across multiple sites' worth of data.

Usage

mpspline(
  obj = NULL,
  var_name = NULL,
  lam = 0.1,
  d = c(0, 5, 15, 30, 60, 100, 200),
  vlow = 0,
  vhigh = 1000
)

Arguments

obj	data.frame or matrix. Column 1 must contain site identifiers. Columns 2 and 3 must contain upper and lower sample depths, respectively. Subsequent columns will contain measured values for those depths.
var_name	length-1 character or length-1 integer denoting the column in obj in which target data is stored. If not supplied, the fourth column of the input object is assumed to contain the target data.
lam	number; smoothing parameter for spline. Defaults to 0.1.
d	sequential integer vector; denotes the output depth ranges in cm. Defaults to c(0, 5, 15, 30, 60, 100, 200) after the GlobalSoilMap specification, giving output predictions over intervals 0-5cm, 5-15cm, etc.
vlow	numeric; constrains the minimum predicted value to a realistic number. Defaults to 0.
vhigh	numeric; constrains the maximum predicted value to a realistic number. Defaults to 1000.

Value

A nested list of data for each input site. List elements are: Site ID, vector of predicted values over input intervals, vector of predicted values for each cm down the profile to max(d), vector of predicted values over d (output) intervals, and root mean squared error.

Examples

dat <- data.frame("SID" = c( 1,  1,  1,  1,   2,   2,   2,   2),
                   "UD" = c( 0, 20, 40, 60,   0,  15,  45,  80),
                   "LD" = c(10, 30, 50, 70,   5,  30,  60, 100),
                  "VAL" = c( 6,  4,  3, 10, 0.1, 0.9, 2.5,   6),
                   stringsAsFactors = FALSE)
m1 <- mpspline(obj = dat, var_name = 'VAL')

mpspline2 documentation built on April 4, 2022, 1:07 a.m.