mpspline_tidy: Spline discrete soils data - multiple sites, tidy output

In obrl-soil/mpspline2: Mass-Preserving Spline Functions for Soil Data

Spline discrete soils data - multiple sites, tidy output

Description

This function implements the mass-preserving spline method of Bishop et al (1999) (\Sexpr[results=rd]{tools:::Rd_expr_doi("10.1016/S0016-7061(99)00003-8")}) for interpolating between measured soil attributes down a soil profile, across multiple sites' worth of data. It returns an output object with tidy data formatting.

Usage

mpspline_tidy(
  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, and be measured in centimeters. 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 four-item list containing data frames of predicted values over the input depth ranges, the output depth ranges, 1cm-increment predictions, and RMSE and IQR-scaled RMSE values.

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)
mpspline_tidy(obj = dat, var_name = 'VAL')

obrl-soil/mpspline2 documentation built on Feb. 1, 2024, 7:55 p.m.