Calculate linear distances between landmarks
A function to calculate linear distances between a set of landmark coordinates (interlandmark distances)
interlmkdist(A, lmks)
A |
A 3D array (p x k x n) containing landmark coordinates for a set of specimens |
lmks |
A matrix or dataframe of landmark addresses for the start and end landmarks defining m linear measurements (can be either 2-x-m or m-x-2). Either the rows or the columns should have names 'start' and 'end' to define landmarks. |
Function takes a 3D array of landmark coordinates from a set of specimens and the addresses for the start and end landmarks defining linear measurements and then calculates the interlandmark distances. The function returns a matrix of linear distances for all specimens. If the 'lmks' matrix has row or column names defining the name of the linear measurements, the returned matrix will use these for column names (see example). If only two interlandmark distances, 'lmks' input must be m x 2.
Function returns a matrix (n x m) of m linear distances for n specimens
Emma Sherratt & Michael Collyer
data(plethodon)
# Make a matrix defining three interlandmark distances
lmks <- matrix(c(8,9,6,12,4,2), ncol=2, byrow=TRUE,
dimnames = list(c("eyeW", "headL", "mouthL"),c("start", "end")))
# where 8-9 is eye width; 6-12 is head length; 4-2 is mouth length
# or alternatively
lmks <- data.frame(eyeW = c(8,9), headL = c(6,12), mouthL = c(4,2),
row.names = c("start", "end"))
A <- plethodon$land
lineardists <- interlmkdist(A, lmks)Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.