geomorph (version 1.1-6)

digitize2d: Digitize 2D landmarks.

Description

An interactive function to digitize two-dimensional(2D) landmarks from .jpg files.

Usage

digitize2d(spec, nlandmarks, scale)

Arguments

spec

Name of jpeg file to be digitized. File names can be written in manually, including paths, or obtained using directory/file manipulation functions e.g., list.files

nlandmarks

Number of landmarks to be digitized.

scale

Length of scale placed in image.

Value

• Function writes to the working directory an NTS file with the name of the specimen and .nts suffix containing the landmark coordinates. Function also returns to console an n x 2 matrix containing the x,y coordinates of the digitized landmarks.

Details

Function for digitizing 2D landmarks on specimen images (.jpg). "nlandmarks" are digitized by the user (see below). The landmarks are "fixed" (traditional landmarks). They can be later designated as "curve sliders" (semilandmarks, that will "slide" along curves lacking known landmarks (see Bookstein 1991:376-382, 1997 for algorithm details) if required. These landmarks are defined as "sliders" using function define.sliders.2d or with similar format matrix made outside R. Digitizing sequence should proceed by selecting all "fixed" landmark points first, followed by selection of "curve sliders". Digitizing{ Digitizing landmarks involves landmark selection using a mouse in the plot window, using the LEFT mouse button (or regular button for Mac users):

1. Digitize the scale bar by selecting the two end points (single click for start and end), NOTE: no dot is printed on the image on the first click; only when both ends have been digitized.
2. Digitize each landmark with single click and the landmark is shown in red, When selection of n landmarks is completed, an ".nts" file is created in working directory using the specimen name, adding ".nts" as a suffix.

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See Also

list.files,