Magnetic trackline data are of central importance in estimating relative plate motions, have allowed a detailed apparent polar wander path to be determined for the Pacific Plate from skewness analysis, and provide important constraints for many other geophysical investigations. Interpreting trackline data typically requires processing, which often involves dividing tracks into quasi-linear segments. Here we present a method for automating this processing step by adapting the Ramer-Douglas-Peucker (RDP) algorithm, originally developed for polygonal approximation and cartographic generalization, for use on trackline data on a sphere and demonstrate its ability to segment data into quasi-linear (i.e., great circle-like) sections quickly based on two intuitive parameters. The new procedure is largely automated and requires minimal effort. As a test and proof of concept, we apply this method to estimate an angular velocity for motion between the Pacific and Rivera plates since 0.781 Ma using data from the NCEI geophysical trackline database. Our modified RDP algorithm identified 400+ track segments that intersected the Rivera Rise, of which more than 50 provided useful Pacific-Rivera spreading rates, which is roughly twice the 26 rates used to estimate Pacific-Rivera motion in the MORVEL set of geologically current plate relative angular . We compare the resulting angular velocity to previous estimates of Pacific-Rivera angular velocity and explore implications for Pacific-North America and Pacific-Cocos relative motion and Rivera absolute motion.