In the last 10 years GPS technology has become widely available due to the proliferation of smart devices with GPS capability. GPS was introduced as a method to assist in location and navigation and is still the most common use for this technology today. Many may not consider that GPS can be used for a variety of different purposes. GPS technology can be used to calculate the distance of activity (running, walking, biking etc.) to build applications to promote exercise and a healthy lifestyle. Calculating this distance accurately is challenging due to the amount of error in GPS location measurements and the low speed of many activities. In this thesis I present methods of calculating distance traveled that reduces this error to produce an accurate distance calculation. I also present an application that uses this distance calculation to help promote children to become more active.