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? It will omit labels where they would abut or overlap previously drawn labels.

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 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_ford(), plot_heatmap(), plot_rank(), 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 Sept. 11, 2024, 6:40 p.m.