Transition Visualization

Input Data

• Cell tower ID and user labels
• Median duration at cell
• Duration is time until next (self) transition
• Durations > 1hr ignored. Expect (self) transitions at least every ~10min.
• Excessively long durations indicative of no reception or data loss (ex: phone off)
• Transition from cell to neighbor only if duration valid
• Count of transitions used for relative distance

GraphViz

GraphViz Node Key

dot

A Typical Friday (dot)

• Aligns top -> down with respect to input ordering
• Fails to organize close or common cells, often resulting in many long, overlapping edges.
• Best edge path routing. No overlapping with nodes or text.

neato

A Typical Friday (neato)

• Spring energy model
• Relative edge length = inverse of # observed transitions
• Common nodes placed centrally
• Poor edge path routing. Text often overlaps with edges, resulting in decreased readability.
• Fails to render very large graphs

Full Pittsburgh Graph (click image to enlarge)

Full Graph (dot)

Full Graph (neato)

Ongoing Work

• Real-time data transmission and visualization (in progress)
• Tuning of neato output to better optimize text alignment
• Integration of bluetooth data (pending bluetooth reliability improvements)