RPMG (version 2.2-7)

breakline.index: Break a vector into segments

Description

Break a vector into segments

Usage

breakline.index(Z, ww)

Value

List of indices that are segments.

Arguments

Z

vector

ww

indices where the breaks should occur. if a matrix is provided the start and end indices are given, else the breaks are provded.

Author

Jonathan M. Lees<[e-mail]>

Details

Codes used for maps to break map segments along boundaries. But this is more general, nd can be used to break any vector according to given indices. See examples.

Examples

###   example with a vector of breaks
h  = 1:20
k = breakline.index(h, c(8, 14))

########  select with a matrix of start-ends
r1 = rbind(c(3,10), c(14, 18))
k = breakline.index(h, r1)

j1 = seq(from=3, to=17, by=3)
j2 = j1+5

##########  overlapping sequences
r1 = cbind(j1, j2)
k = breakline.index(h, r1)

######  example with coordinates

####  some data:
uu=list()
uu$x=c(136.66,136.34,136.07,136.07,135.62,135.03,134.98,
134.98,135.07,135.25,135.75,137.07,137.35,137.44,138.07,
138.07,137.80,137.75,137.25)
uu$y=c(39.878,39.749,39.490,39.296,39.200,39.135,38.909,
38.618,38.327,38.004,37.875,37.875,38.327,38.489,
38.812,39.006,39.232,39.587,39.943)

###  plot raw data
plot(uu$x, uu$y, type="l")

####  cutoff:
z1 = 39

h = 1:length(uu$x)

w1 = which( uu$y>z1)

g1 = list(x=uu$x[w1] , y=uu$y[w1] )

lines(g1, col='red')
############   notice the connecting line.
#########  how can we avoid this?

w2 = which(diff(w1)!=1)

k = breakline.index(w1, w2)

for(i in 1:length(k)) lines(uu$x[ k[[i]] ], uu$y[ k[[i]]  ], col='blue')
######  see, line is broken correctly