Plotting a heatmap of Kriging with coordinate in R

Question

I performed Kriging in R. But I have trouble getting a plot of a colored heatmap showing the resulted interpolated area along with a lon/lat values at the side and on the button.

Here is an example, what I want:

Here is my code so far:

kerpensample_df <- read.csv("C:\\Users\\49151\\Desktop\\kerpentest0909x.csv",
                         header=TRUE, stringsAsFactors=FALSE, sep = ",")
                       
head(kerpensample_df)

kerpensample_sf = st_as_sf(kerpensample_df, coords = c("X", "Y"), crs =32632)

v_emp_OK <- gstat::variogram(
  Z~1,
  as(kerpensample_sf, "Spatial")
)

plot(v_emp_OK)

v_mod_OK = autofitVariogram(Z~1, as(kerpensample_sf, "Spatial"))$var_model

plot(autofitVariogram(Z~1, as(kerpensample_sf, "Spatial")))

ggplot(
  data = kerpensample_df,
  mapping = aes(x = X, y =Y, color = Z)
) +
  geom_point(size = 3) +
  scale_color_viridis_b() +
  theme_classic()

grid = st_as_stars(st_bbox(st_buffer(kerpensample_sf, 0.001)))
OK <- krige(
  Z~1,
  as(kerpensample_sf, "Spatial"),
  grid, 
  model = v_mod_OK
)

plot(OK)

Here is my csv: https://ufile.io/l1wmw1te

It can probably be done with ggplot function, but I have no clue.

Answer 1

Here is a possible solution using akima & ggplot2.

#dependencies
library(ggplot2)
library(tidyr)
library(akima)
#set working directory
setwd('C:/Path/to/data')
df <- read.csv('kerpentest0909x.csv')
#interpolate missing values
my.df.interp <- interp(x = df$X, y = df$Y, z = df$Z, nx = 200, ny = 200) 
df_new <- as.data.frame(interp2xyz(my.df.interp))
#rename columns
names(df_new) <- c("X", "Y", "Z")
#compute mean Z
mean_Z <- mean(df_new$Z, na.rm = TRUE)
#replace NA with mean Z value
df_new <- df_new %>% dplyr::mutate(Z = replace_na(Z, mean_Z))
#create list of colors
colors = c('deeppink', 'blue3', 'aquamarine', 'chartreuse', 'yellow', 'darkorange1', 'red')
#create plot
ggplot(df_new, aes(X, Y, z = Z)) +
  stat_summary_2d(geom = "raster", bins = 150) +
  scale_fill_gradientn(colours = colors) 

Output:

Adapted from the answers here and here.