readland.tps: Read landmark data from tps file

Description

Read *.tps file to obtain landmark coordinates

Usage

readland.tps(file, specID = c("None", "ID", "imageID"), readcurves = FALSE, warnmsg = T)

Arguments

file

A *.tps file containing two- or three-dimensional landmark data

specID

a character specifying whether to extract the specimen ID names from the ID or IMAGE lines (default is "None").

readcurves

A logical value stating whether CURVES= field and associated coordinate data will be read as semilandmarks (TRUE) or ignored (FALSE).

warnmsg

A logical value stating whether warnings should be printed

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 image names in the *.tps file.

Details

This function reads a *.tps file containing two- or three-dimensional landmark coordinates. Tps files are text files in one of the standard formats for geometric morphometrics (see Rohlf 2010). Two-dimensional landmarks coordinates are designated by the identifier "LM=", while three-dimensional data are designated by "LM3=". Landmark coordinates are multiplied by their scale factor if this is provided for all specimens. If one or more specimens are missing the scale factor, landmarks are treated in their original units. Missing data may be present in the file. In this case, they must be designated by 'NA'. The positions of missing landmarks may then be estimated using estimate.missing.

The user may specify whether specimen names are to be extracted from the 'ID=' field or 'IMAGE=' field and included in the resulting 3D array. e.g., for 'ID=' use (file, specID = "ID") and for 'IMAGE=' use (file, specID = "imageID"). The default is specID="None".

If there are curves defined in the file (i.e., CURVES= fields), the option 'readcurves' should be used. When readcurves = TRUE, the coordinate data for the curves will be returned as semilandmarks and will be appended to the fixed landmark data. Then the user needs to use define.sliders or define.sliders to create a matrix designating how the curve points will slide (used by 'curves=' in gpagen). When readcurves = FALSE, only the landmark data are returned.

NOTE: At present, all other information that can be contained in tps files (comments, variables, radii, etc.) is ignored.

References

Rohlf, F. J. 2010. tpsRelw: Relative warps analysis. Version 1.49. Department of Ecology and Evolution, State University of New York at Stony Brook, Stony Brook, NY.