Abstract: Using aggregate activity data to generate a grade adjusted pace model is disclosed, including: receiving a plurality of activities; selecting a portion of the plurality of activities based at least in part on recorded heart rate information associated with the plurality of activities; and generating a Grade Adjusted Pace (GAP) model based at least in part on the selected portion of the plurality of activities.

Abstract: A cutting and threshing blade for a bush hog, wherein the blade has a trailing edge and a leading edge. At least a third of the leading edge of the upper-side of an elongate distal portion of the blade has a knife edge with a knife length that thickens toward the trailing edge. The trailing edge can have an upward air deflector. The bottom-side of the elongate distal portion has a threshing element, which includes a threshing block, which is a steel block having a block length that is comparable to the knife length and projects downward and substantially parallel to the knife edge. The rotating blades pummel growth carriers (i.e.; cob, husk) bearing seeds, grains, and kernels with enough force that they are released. The synergistic rotating knife edge and threshing block transform the bush hogging process from a cutting process to a cutting and threshing process.

Abstract: Determining clusters of similar activities is disclosed, including: receiving a plurality of activities, wherein an activity included in the plurality of activities includes GPS data recorded using a GPS recording device; determining a cluster of similar activities from the plurality of activities; and generating a map display for the cluster of similar activities.

Abstract: A cutting and threshing blade for a bush hog, wherein the blade has a trailing edge and a leading edge. At least a third of the leading edge of the upper-side of an elongate distal portion of the blade has a knife edge with a knife length that thickens toward the trailing edge. The trailing edge can have an upward air deflector. The bottom-side of the elongate distal portion has a threshing element, which includes a threshing block, which is a steel block having a block length that is comparable to the knife length and projects downward and substantially parallel to the knife edge. The rotating blades pummel growth carriers (i.e.; cob, husk) bearing seeds, grains, and kernels with enough force that they are released. The synergistic rotating knife edge and threshing block transform the bush hogging process from a cutting process to a cutting and threshing process.

Abstract: Detecting group activities is disclosed, including: receiving a plurality of GPS recorded activities uploaded by a plurality of athletes, wherein the plurality of athletes comprises a first athlete and a second athlete; receiving a request to determine a set of group activities that includes the first athlete and the second athlete; determining the set of group activities based at least in part on a set of time criteria and a set of space criteria used to compare a first GPS recorded activity associated with the first athlete and a second GPS recorded activity associated with the second athlete; and outputting at least some of the set of group activities.

Abstract: Determining clusters of similar activities is disclosed, including: receiving a plurality of activities, wherein an activity included in the plurality of activities includes GPS data recorded using a GPS recording device; determining a cluster of similar activities from the plurality of activities; and generating a map display for the cluster of similar activities.