coo_slice {Momocs}

Slices shapes between successive coordinates

Description

Takes a shape with n coordinates. When you pass this function with at least two ids (<= n), the shape will be open on the corresponding coordinates and slices returned as a list

Usage

coo_slice(coo, ids, ldk)

Arguments

coo

matrix of ⁠(x; y)⁠ coordinates or any Coo object.

ids

numeric of length >= 2, where to slice the shape(s)

ldk

numeric the id of the ldk to use as ids, only on Out and Opn. If provided, ids will be ignored.

Value

a list of shapes or a list of Opn

See Also

Have a look to coo_slidegap if you have problems with gaps after slicing around landmarks and/or starting points.

Other coo_ utilities: coo_aligncalliper(), coo_alignminradius(), coo_alignxax(), coo_align(), coo_baseline(), coo_bookstein(), coo_boundingbox(), coo_calliper(), coo_centdist(), coo_center(), coo_centpos(), coo_close(), coo_down(), coo_dxy(), coo_extract(), coo_flipx(), coo_force2close(), coo_interpolate(), coo_is_closed(), coo_jitter(), coo_left(), coo_likely_clockwise(), coo_nb(), coo_perim(), coo_range(), coo_rev(), coo_right(), coo_rotatecenter(), coo_rotate(), coo_sample_prop(), coo_samplerr(), coo_sample(), coo_scale(), coo_shearx(), coo_slidedirection(), coo_slidegap(), coo_slide(), coo_smoothcurve(), coo_smooth(), coo_template(), coo_trans(), coo_trimbottom(), coo_trimtop(), coo_trim(), coo_untiltx(), coo_up(), is_equallyspacedradii()

Examples

h <- slice(hearts, 1:5)  # speed purpose only
# single shape, a list of matrices is returned
sh <- coo_slice(h[1], c(12, 24, 36, 48))
coo_plot(sh[[1]])
panel(Opn(sh))
# on a Coo, a list of Opn is returned
# makes no sense if shapes are not normalized first
sh2 <- coo_slice(h, c(12, 24, 36, 48))
panel(sh2[[1]])

# Use coo_slice with `ldk` instead:
# hearts as an example
x <- h %>% fgProcrustes(tol=1)
# 4 landmarks
stack(x)
x$ldk[1:5]

# here we slice
y <- coo_slice(x, ldk=1:4)

# plotting
stack(y[[1]])
stack(y[[2]])

# new ldks from tipping points, new ldks from angle
olea %>% slice(1:5) %>% # for the sake of speed
def_ldk_tips %>%
def_ldk_angle(0.75*pi) %>% def_ldk_angle(0.25*pi) %>%
coo_slice(ldk =1:4) -> oleas
oleas[[1]] %>% stack
oleas[[2]] %>% stack # etc.

# domestic operations
y[[3]] %>% coo_area()
# shape analysis of a slice
y[[1]] %>% coo_bookstein() %>% npoly %>% PCA %>% plot(~aut)