Meeting point planning based on preceding GPS positions

Myth is a research and development project at the Applied Mobile Research group, and is part of the location-based mobile application series "HeyYouThere". The purpose of this project is to develop an application for Symbian-based, GPS-capable cell phones, which application recommends meeting points to its users. Anytime two users are scheduling a meeting, the application helps them by presenting numerous possible meeting points. These points include the location, time, and probability of an optimal meeting with these parameters. These points are calculated based on the time, the date and the places and routes where the user usually travels. This information is collected by the application over time, using the built-in or connected GPS device, and stored in a database on the phone.

How does it work?

The user usually takes the same routes to travel to work, school, shopping, etc. He usually passes the same way at around the same time, each day, or each week, periodically. He might also take alternate paths with different probabilities. This suggests that only the first period should be stored from the measured data, which is only a week or a day long, allowing using the subsequent periods’ data points to refine the nearby points from the first period. This also makes possible to calculate the probability between alternate routes, which are on the same time, but not at the same place. Collecting the location information of the users is simply made by GPS-enabled Nokia devices (e.g. N95.).

Averaging coordinates emerges some questions: Which previously stored point should be averaged with the new one? How should the averaging be done? When should the point be stored as a new point instead of refining an old one? With our client, we tried to find the answers for these questions.

Calculating the meeting point

When two people want to meet, they can choose between numerous rendezvous points. These points vary in the exact time of the rendezvous, in distance, they have to walk to the rendezvous point, in time, they have to wait for each other, and in probability, that both of them will take the proper routes. From these parameters, the users can specify a time or a time frame, where the rendezvous should take place, a maximal walking distance, a maximal waiting time, and a minimal probability. To find the optimal meeting point, the best points should be found in each category in the specified time frame. These are the smallest distance and smallest waiting time points, and a point between these two. The probability parameter is not so important to make calculations with it; it is rather extra information to the user, like a route is a one-shot route or he usually takes that one.

For investigation purposes, we have a Desktop-based software where the meeting point calculation can be examined.

At the following link, you can watch a video where we explain the idea behind the meeting point calculation: http://www.aut.bme.hu/portal/myth/MeetingPoint.wmv

The S60 application

The user can see his actual position on a map, along with the routes he has already gone. Zooming and browsing on the map is available. The GPS receiver can be turned on and off manually, and the recording of data can be turned off as well.

He can list the routes, their parameters, like start time and end time, length, probability, last time he was there. The routes can be selected from a list, or from the map. He can synchronize with another user’s device over Bluetooth or WLAN, to agree on a rendezvous in the future. Time frame and other parameters can be set. They can choose a comfortable rendezvous point from the multiple suggested points, presented application. The chosen rendezvous point is then saved in the agenda, and it is shown on the map till the rendezvous.

For testing purposes, we made the client prototype available, please contact bertalan.forstnerWRITEATTHEREaut.bme.hu. Any comments are welcome.

The idea and concepts of the HeyYouThere location-based applications is from Bertalan Forstner from Amorg. Research and development in case of the MeetYouThere application was made by István Engedy.