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Field map of a checked uniformity trial

Source: R/plot_trial_check.R
plot.trial_check.Rd

Draws the trial as a map: an ordinary-kriging surface built from the variogram fitted by check_trial(), with the basic experimental units drawn on top and filled on the same colour scale. The surface shows where the field is systematically better or worse; the points show the data the surface came from, so an interpolation artefact cannot be mistaken for a measurement.

Usage

# S3 method for class 'trial_check'
plot(
  x,
  resolution = 120,
  points = TRUE,
  point_values = TRUE,
  point_size = 2.4,
  point_stroke = 0.4,
  point_colour = "grey20",
  surface = TRUE,
  palette = c("viridis", "blues", "greys", "terrain"),
  title = NULL,
  subtitle = NULL,
  caption = NULL,
  legend_title = NULL,
  xlab = "Row",
  ylab = "Column",
  base_size = 12,
  family = "sans",
  ...
)

Arguments

x

an object of class "trial_check".

resolution

number of interpolation cells along the longer side of the field (default 120). The surface costs one linear solve, so raising this is cheap.

points

logical; draw the basic units (default TRUE).

point_values

logical; fill the points with their own value (default TRUE). FALSE draws them as plain markers, showing only the sampling positions.

point_size, point_stroke, point_colour

size of the unit markers, the width of their outline, and its colour. A dark rim keeps the markers visible over the pale end of any palette.

surface

logical; draw the kriged surface (default TRUE). With FALSE only the units are drawn, which is the honest picture when the variogram shows weak spatial dependence.

palette

one of "viridis" (default), "blues", "greys" or "terrain". The default is perceptually uniform and readable in greyscale and to colour-blind readers, which several journals now require; "blues" gives the classic look.

title, subtitle, caption, legend_title

plot labels. NULL leaves a sensible default; NA removes the element.

xlab, ylab

axis titles.

base_size, family

base font size and family.

...

ignored.

Value

A ggplot object.

Details

With several trials the maps are faceted and share one colour scale, which is what makes them comparable.

See also

check_trial()

Examples

grid1 <- as.matrix(uniformity_trial[uniformity_trial$trial == "T1",
                                    grep("^col", names(uniformity_trial))])
chk <- check_trial(grid1)
#> Checking 1 trial(s).

# \donttest{
plot(chk)


## the classic look, and points as plain position markers
plot(chk, palette = "blues", point_values = FALSE)


## data only, no interpolation
plot(chk, surface = FALSE)

# }