Methods to handle spatial eigenvector maps of a set of locations in a space with an arbitrary number of dimension.
# S3 method for eigenmap
print(x, ...)
# S3 method for eigenmap
plot(x, ...)An object of eigenmap-class
Further parameters to be passed to other functions or methods (currently ignored).
eigenmap-class objects contain:
a matrix of coordinates,
the interval within which pairs of sites are considered as neighbour,
the distance matrix,
the weighting function that had been used,
the weighting function parameter that had been used,
a vector of the eigenvalues obtain from the computation of the eigenvector map, and
a matrix of the eigenvectors defining the eigenvector map.
The print method provides the number of the number of
orthonormal variables (i.e. basis functions), the number of
observations these functions are spanning, and their associated
eigenvalues.
The plot method provides a plot of the eigenvalues and offers
the possibility to plot the values of variables for 1- or
2-dimensional sets of coordinates. plot.eigenmap opens the default
graphical device driver, i.e., X11, windows, or
quartz and recurses through variable with a left mouse click on
the graphical window. A right mouse click interrupts recursing on
X11 and windows (Mac OS X users should hit Esc on
the quartz graphical device driver (Mac OS X users).
Dray, S.; Legendre, P. and Peres-Neto, P. 2006. Spatial modelling: a comprehensive framework for principal coordinate analysis of neighbor matrices (PCNM). Ecol. Modelling 196: 483-493