Fig. 4

Axis conventions. A MainCATSprhTool.m analyzes tags with a right-hand orientation such that rotation around each axis is counterclockwise (when viewed from the positive direction of the rotation axes), and heading and pitch have intuitive orientations (+ pitch is up, + heading is like a compass). In standard position (e.g., a whale at the surface), [x y z] = [0 0 − 1] g, where g is acceleration due to gravity. B Standard DTAG processing, as utilized by the scripts available at http://www.animaltags.org/, uses a left-hand orientation with heading and pitch oriented intuitively and roll assigned arbitrarily to be clockwise (to the animal’s left). In standard position [x y z] = [0 0 1] g. To convert between CATS conventions and DTAG conventions, multiply z-axis values and roll by − 1. C Live view display of a tag flat on a table as in panel A, whose axis conventions align with the processing conventions. D If instead the display in C is for a tag oriented as in the image, it implies that the third axis is actually displaying the –y orientation, so the axAo variable in axisconventions.m would need to be adjusted as in Eq. 1. In this example, the first two positions are left blank, because they have not yet been tested. Illustrations by Jessica Bender