readmulti.nts: Read landmark data from multiple nts files

Description

Read a list of names for several *.nts files to obtain landmark coordinates for a set of specimens

Usage

readmulti.nts(filelist)

Arguments

filelist

A list of names for the *.nts files to be read by the function. The names in the list require quotes (") and .nts/.NTS suffix.

Value

Function returns a (p x k x n) array, where p is the number of landmark points, k is the number of landmark dimensions (2 or 3), and n is the number of specimens. The third dimension of this array contains names for each specimen, which are obtained from the original file names.

Details

This function reads a list containing the names of multiple *.nts files, where each contains the landmark coordinates for a single specimen. For these files, the number of variables (columns) of the data matrix will equal the number of dimensions of the landmark data (k=2 or 3). When the function is called a dialog box is opened, from which the user may select multiple *.nts files. These are then read and concatenated into a single matrix for all specimens. The parameter line contains 5 or 6 elements, and must begin with a "1" to designate a rectangular matrix. The second and third values designate how many specimens (n) and how many total variables (p x k) are in the data matrix. The fourth value is a "0" if the data matrix is complete and a "1" if there are missing values. If missing values are present, the '1' is followed by the arbitrary numeric code used to represent missing values (e.g., -999). These values will be replaced with "NA" in the output array. Subsequent analyses requires a full complement of data, see estimate.missing.

Missing data may be present in the file by designating them using 'NA'. In this case, the standard NTSYS header is used with no numeric designation for missing data (i.e. the fourth value is '0'). The positions of missing landmarks may then be estimated using estimate.missing.