An S4 class to represent a stratigraphic matrix.

A stratigraphic matrix represents directed relationships between stratigraphic units. A stratigraphic matrix is an adjacency matrix (a non symmetric square matrix with zeros on its main diagonal), suitable to build a directed acyclic graph (DAG).

Other matrix:
`CompositionMatrix-class`

,
`CountMatrix-class`

,
`DataMatrix`

,
`IncidenceMatrix-class`

,
`OccurrenceMatrix-class`

,
`coerce()`

N. Frerebeau

# Principles of Archaeological Stratigraphy, fig. 12 harris <- matrix( data = c(2, 1, 3, 1, 4, 1, 5, 2, 5, 3, 5, 4, 6, 5, 7, 1, 7, 6, 8, 1, 8, 6, 9, 7, 9, 8), ncol = 2, byrow = TRUE, dimnames = list(NULL, c("lower", "upper")) ) strati <- as_stratigraphy(harris)