# Part 3 - Mark Waypoints with GPS

## Step 1 – Prepare to Mark Waypoints

In this section of the activity you will use a GPS, go outside, and mark the waypoints for litter and trashcans found around the site of your choice.

1. Decide on the distribution and quantity of litter necessary to be considered as a waypoint before collecting waypoints. For example consider the following:
• If there are three bottle caps on the ground, will that be 3 waypoints, or will that be one?
• Decide how far apart each piece of litter needs to be from one another to be considered a separate waypoint. If the three bottle caps were within 20cm, would that be different than if they were separated by 1 meter ? Note: Be sure to consider the precision of your unit when making this decision; most units cannot resolve points that are so close together.
• Look at the picture below. Discuss the following questions: How many pieces of litter is this? Will this be one waypoint, or three?

2. If working in groups, decide who will a) mark the waypoints, b) record the data, c) be the litter scout, and d) take pictures of the litter.
3. Optional: Click on this link to download a data recording sheet (Acrobat (PDF) PRIVATE FILE 36kB Sep28 10) (in PDF) for use in this exercise.
4. If you haven't already done so, exit out of Demo mode by turning the GPS off. Once outside, turn on the GPS on and wait until the GPS has a good signal from at least four satellites.
5. If necessary, clear previous Waypoints on the GPS unit.

## Step 2 – Mark Waypoints of Litter

1. Most GPS units have an antenna located such that the unit functions best when held parallel to the ground with the screen facing the sky. For best results, be sure to keep the GPS in this position.
2. Mark the waypoints of litter and trash cans in addition to recording the data on a data sheet. Pick up the litter and dispose of it in a trash can. Collect at least 10 litter data points.
3. Periodically, use Find to check the waypoint list to be sure that the litter waypoints are being recorded and saved.
4. If working in a group, rotate jobs amongst the team so that everyone tries each task.
5. When you are done recording data, return to the central location designated by your instructor.