geomorph (version 1.1-1)

digit.curves: Select points to "slide" along three-dimensional curves.

Description

A function to select points which will "slide" along three-dimensional curves.

Usage

digit.curves(n, curves)

Arguments

n

Number of total "fixed" and curve sliding landmarks.

curves

Number of landmarks to slide along curves.

Value

• Function returns a matrix containing the landmark adress of the curve sliders, indicating the points between which the selected point will "slide". In addition, the function returns a .csv file to be used by gpagen during GPA.

Details

This function helps user select points on the created template to "slide" along curves lacking known landmarks (see Bookstein 1991:376-382, 1997 for algorithm details). Each sliding semi-landmark (sliders) will slide between two designated points, along a line tangent to the specified curvature. template.txt file must be in current working directory.

1. Select the first point between which semi-landmark will "slide"
2. Select sliding point,
3. Select point along which sliding trajectory will end. Screen will show lines connecting the three points, and will highlight the sliding semilandmark in red.

Digitizing{ Digitizing using buildtemplate is interactive between landmark selection using a mouse (see below for instructions), and the R console. Once a point is selected, the user is asked if the system should keep or discard the selection #'(y/n). If "y", the user is asked to continue to select the next landmark.If "n" the removes the last chosen landmark, and the user is askesd to select it again. This can be repeated until the user is comfortable with the landmark chosen. To digitize with a standard 3-button (PC) buildtemplate uses:

1. the RIGHT mouse button (primary) to select points to be digitized First,
2. the LEFT mouse button (secondary) is used to rotate mesh,
3. the mouse SCROLLER (third/middle) is used to zoom in and out.

Note: Digitizing functions on MACINTOSH computers using a standard 3-button mice works as specified. Macs using platform specific single button mice:

1. press button to rotate 3D mesh,
2. press button while pressing CONTROL key to select points to be digitized,
3. press button while pressing OPTION key to adjust mesh perspective.

Mac mouse settings need adjustment to acquire zooming functions of the "middle/third" mouse button/scroller. Some instructions can be found at http://blog.boastr.net/. In addition, freeware providing "Middle Click" functionality is available at http://magicprefs.com/ for "magicmice" now standard on many Macintosh machines. }

References

Bookstein, F. J. 1991 Morphometric Tools for Landmark Data: Geometry and Biology. Cambridge University Press, New York. Bookstein, F. J. 1997 Landmark Methods for Forms without Landmarks: Morphometrics of Group Differences in Outline Shape. Medical Image Analysis 1(3):225-243.

See Also

digitsurface, gpagen