geomorph (version 1.1-1)

estimate.missing: Estimate locations of missing landmarks using the thin-plate spline

Description

A function for estimating the locations of missing landmarks

Usage

estimate.missing(ref, target)

Arguments

ref

Landmark coordinates of a reference specimen

target

Landmark coordinates of a target specimen (contains -999 for missing landmarks)

Value

• Function returns a n * p matrix of coordinates for the target specimen that includes the original landmarks plus the estimated coordinates for the missing landmarks.

Details

The function estimates the locations of missing landmarks on a target specimen based on the locations of the corresponding landmarks on a complete, reference specimen. Missing landmarks in a target specimen are designated by '-999' in place of the x,y,z coordinates. First, a complete reference specimen is aligned to a target specimen (missing one or more landmarks), using the set of landmarks common to both specimens. Next, the thin-plate spline interpolating function is used to estimate the locations of the missing landmarks in the target specimen.

References

Bookstein, F. L., K. Schafer, H. Prossinger, H. Seidler, M. Fieder, G. Stringer, G. W. Weber, J.-L. Arsuaga, D. E. Slice, F. J. Rohlf, W. Recheis, A. J. Mariam, and L. F. Marcus. 1999. Comparing frontal cranial profiles in archaic and modern Homo by morphometric analysis. Anat. Rec. (New Anat.) 257:217-224. Gunz, P., P. Mitteroecker, S. Neubauer, G. W. Weber, and F. L. Bookstein. 2009. Principles for the virtual reconstruction of hominin crania. J. Hum. Evol. 57:48-62.

Examples

data(plethodon)
ref<-plethodon$land[,,1]
target<-plethodon$land[,,11]
target[2,]<-target[6,]<- -999    #create some missing landmarks
estimate.missing(ref,target)