Semivariograms

Alex Koiter

Load libraries

In [1]:

suppressPackageStartupMessages({
  library(tidyverse)
  library(readODS)
  library(gt)
})

Warning: package 'readODS' was built under R version 4.4.3

Data

In [2]:

vario <- read_ods(here::here("./notebooks/semivariogram.ods")) %>%
  mutate(sill = p_sill + nugget, 
         `C/(C + Co) (%)` = 100 * p_sill/sill,
         `Spatial Class` = case_when(`C/(C + Co) (%)` > 75 ~ "Strong",
                           `C/(C + Co) (%)`<=75 & `C/(C + Co) (%)` >25 ~ "Moderate",
                           `C/(C + Co) (%)` < 0.25 ~ "Low")) %>%
  select("Property" = "property", "Kriging Type" = "model", "Nugget (Co)" = "nugget", "Sill (Co + C)" = "sill", "C/(C + Co) (%)", "Range (m)" = "range", "site", "r2", "Spatial Class") %>%
  #select(-p_sill) %>%
  mutate(Property = fct_relevel(Property, "Ca", "Co", "Cs", "Fe", "Li", "La", "Nb", "Ni", "Rb", "Sr", "a*", "b*", "c*", "h*", "x")) %>%
  arrange(Property)

In [3]:

In [4]:

vario |>
  group_by(site) |>
  gt() |>
  fmt_number(decimal = 1) |>
  fmt_number(columns = c("Range (m)", "C/(C + Co) (%)"), decimal = 0) |>
  cols_label(r2 = "{{r^2}}") |>
  tab_footnote(
    footnote = "Models are all isotropic.",
    locations = cells_column_labels(columns = "Kriging Type"))  |>
  tab_footnote(
    footnote = "Strong spatial dependency (C/(C + Co) % >75); Moderate spatial dependency (C/(C + Co) % between 75 and 25); Low spatial dependency (C/(C + Co) % <25).",
    locations = cells_column_labels(columns = `Spatial Class`))  |>
  tab_style(style =  cell_text(weight = "bold", align = "center"), locations =  cells_row_groups()) |>
  tab_options(column_labels.font.weight = "bold")

Table 1: Geostatistical parameters of the fitted semivariogram models of selected colour and geochemical properties within the agricultural and forested sites.

Property	Kriging Type¹	Nugget (Co)	Sill (Co + C)	C/(C + Co) (%)	Range (m)	r²	Spatial Class²
Agriculture
Ca	Universal	0.0	7.2	100	580	0.9	Strong
Co	Simple	0.0	0.7	100	208	0.4	Strong
Cs	Ordinary	0.0	0.0	100	210	0.5	Strong
Fe	Ordinary	0.0	0.0	100	185	0.2	Strong
Li	Universal	0.3	1.5	81	185	0.6	Strong
La	Simple	0.4	1.0	56	308	0.5	Moderate
Nb	Universal	0.0	0.0	91	210	0.7	Strong
Ni	Ordinary	1.4	8.9	84	352	0.6	Strong
Rb	Ordinary	1.4	27.6	95	551	0.9	Strong
Sr	Ordinary	0.9	900.2	100	220	1.0	Strong
a*	Ordinary	0.4	1.0	59	288	0.3	Moderate
b*	Simple	0.2	0.9	83	199	0.3	Strong
c*	Simple	0.1	0.9	87	199	0.3	Strong
h*	Simple	0.0	1.1	100	185	0.2	Strong
x	Simple	0.4	1.0	58	220	0.1	Moderate
Forest
Ca	Ordinary	1.6	2.7	41	269	0.2	Moderate
Co	Ordinary	0.0	2.1	100	298	0.1	Strong
Cs	Ordinary	0.0	0.0	83	237	0.2	Strong
Li	Ordinary	0.0	0.8	100	222	0.3	Strong
La	Ordinary	3.1	7.4	59	176	0.1	Moderate
Nb	Ordinary	0.0	0.0	51	224	0.2	Moderate
Ni	Universal	6.7	15.8	57	187	0.2	Moderate
Sr	Simple	0.4	1.0	65	229	0.4	Moderate
h*	Universal	0.0	0.0	100	230	0.3	Strong
¹ Models are all isotropic.
² Strong spatial dependency (C/(C + Co) % >75); Moderate spatial dependency (C/(C + Co) % between 75 and 25); Low spatial dependency (C/(C + Co) % <25).