We have developed object-oriented programming methods to enable avatar movement across the Google Earth surface in response to student actions. Students travel on their own, or in groups attached to a field vehicle avatar (a Jeep). Students communicate using text messages sent from their web pages to balloons that pop up from the avatars in Google Earth. Students can be located locally in a lab class or at great distances from one another, as in a distance education course.

Our programming methods help to create a more engaging virtual field trip in which the students take the lead and decide where to go rather than simply reading text and viewing graphics in a tour designed by their instructor. The user interactivity via avatars is controlled by JavaScript and PHP. Since the position of each avatar is known, it is possible to track their movements and offer text-message advice when students stray off-task or wander about aimlessly. Our methods will be included in new virtual field trips being developed for Iceland, Hawaii, and other locations.