sfourier_i {Momocs}

Inverse radii variation Fourier transform

Description

sfourier_i uses the inverse radii variation (equally spaced curvilinear abscissa) transformation to calculate a shape, when given a list with Fourier coefficients, typically obtained computed with sfourier.

Usage

sfourier_i(rf, nb.h, nb.pts = 120, dtheta = FALSE)

Arguments

rf

A list with ao, an and bn components, typically as returned by sfourier.

nb.h

integer. The number of harmonics to calculate/use.

nb.pts

integer. The number of points to calculate.

dtheta

logical. Whether to use the dtheta correction method. FALSE by default. When TRUE, tries to correct the angular difference between reconstructed points; otherwise equal angles are used.

Value

A list with components:

x

vector of x-coordinates.

y

vector of y-coordinates.

angle

vector of angles used.

r

vector of radii calculated.

References

Renaud S, Pale JRM, Michaux JR (2003): Adaptive latitudinal trends in the mandible shape of Apodemus wood mice. J Biogeogr 30:1617-1628.

See Also

Other sfourier: sfourier_shape(), sfourier()

Examples

coo <- coo_center(bot[1]) # centering is almost mandatory for sfourier family
coo_plot(coo)
rf  <- sfourier(coo, 12)
rf
rfi <- sfourier_i(rf)
coo_draw(rfi, border='red', col=NA)