seriograph: Seriograph

In tabula: Analysis and Visualization of Archaeological Count Data

Seriograph

Description

• seriograph() produces a Ford diagram highlighting the relationships between rows and columns.

• eppm() computes for each cell of a numeric matrix the positive difference from the column mean percentage.

Usage

seriograph(object, ...)

eppm(object, ...)

## S4 method for signature 'matrix'
eppm(object)

## S4 method for signature 'data.frame'
eppm(object)

## S4 method for signature 'matrix'
seriograph(
  object,
  weights = FALSE,
  fill = "darkgrey",
  border = NA,
  axes = TRUE,
  ...
)

## S4 method for signature 'data.frame'
seriograph(
  object,
  weights = FALSE,
  fill = "darkgrey",
  border = NA,
  axes = TRUE,
  ...
)

Arguments

object	A m \times p numeric matrix or data.frame of count data (absolute frequencies giving the number of individuals for each category, i.e. a contingency table).
...	Currently not used.
weights	A logical scalar: should the row sums be displayed?
fill	The color for filling the bars.
border	The color to draw the borders.
axes	A logical scalar: should axes be drawn on the plot?

Details

The positive difference from the column mean percentage (in french "écart positif au pourcentage moyen", EPPM) represents a deviation from the situation of statistical independence. As independence can be interpreted as the absence of relationships between types and the chronological order of the assemblages, EPPM is a useful tool to explore significance of relationship between rows and columns related to seriation (Desachy 2004).

seriograph() superimposes the frequencies (grey) and EPPM values (black) for each row-column pair in a Ford diagram.

Value

• seriograph() is called it for its side-effects: it results in a graphic being displayed (invisibly returns object).

• eppm() returns a numeric matrix.

Author(s)

N. Frerebeau

References

Desachy, B. (2004). Le sériographe EPPM: un outil informatisé de sériation graphique pour tableaux de comptages. Revue archéologique de Picardie, 3(1), 39-56. \Sexpr[results=rd]{tools:::Rd_expr_doi("10.3406/pica.2004.2396")}.

See Also

plot_ford()

Other plot methods: matrigraph(), plot_bertin(), plot_diceleraas(), plot_diversity, plot_ford(), plot_heatmap(), plot_rank(), plot_rarefaction, plot_spot()

Examples

## Data from Desachy 2004
data("compiegne", package = "folio")

## Seriograph
seriograph(compiegne)
seriograph(compiegne, weights = TRUE)

## Compute EPPM
counts_eppm <- eppm(compiegne)
plot_heatmap(counts_eppm, col = khroma::color("YlOrBr")(12))

tabula documentation built on Aug. 22, 2023, 5:11 p.m.