FieldSimR (version 1.4.0)

theoretical_variogram: Theoretical variogram

Description

Creates a theoretical variogram for a separable first order autoregressive (AR1) process.

Usage

theoretical_variogram(
  ncols = 10,
  nrows = 20,
  varR = 1,
  col.cor = 0.5,
  row.cor = 0.7,
  prop.spatial = 1
)

Value

A theoretical variogram with x- and y-axes displaying the row and column displacements, and the z-axis displaying the semivariances (variogram ordinates) for a separable autoregressive process.

Arguments

ncols

A scalar defining the number of columns.

nrows

A scalar defining the number of rows.

varR

A scalar defining the error variance.

col.cor

A scalar defining the column autocorrelation,

row.cor

A scalar defining the row autocorrelation.

prop.spatial

A scalar defining the proportion of spatial trend.

Examples

# Theoretical variogram for a field trial with 10 columns and 20 rows, based
# on column and row autocorrelations of 0.5 and 0.7, and a proportion of
# spatial trend of 0.5. The remaining proportion represents random error.

variogram <- theoretical_variogram(
  ncols = 10,
  nrows = 20,
  varR = 1,
  col.cor = 0.5,
  row.cor = 0.7,
  prop.spatial = 0.5
)

# Theoretical variogram
variogram

# Extract the data frame with the column and row displacements, and the
# theoretical semivariances.
variogram_df <- variogram$data