Interesting Interval Discovery on Spatiotemporal Datasets Csci 8715 Fall 2013

Sub-path of Abrupt Change Spatial sub-path of Abrupt Change[1] –Sharp change in vegetation cover –Transition between ecological zones (ecotones) –Vulnerable to climate change –Moves in response to climate change The change is persistent and rapid W 1 =[12N, 17N] A snapshot of vegetation cover in Africa [6]

Sub-path of Abrupt Change Temporal sub-path (interval) of Abrupt Change[1] ৹ Abrupt shift in precipitation, temperature, etc. ৹ Climate change detection. Raw Sahel precipitation anomaly (JJASO) Smoothed Sahel precipitation anomaly (JJASO)

Case Study Output AVG{∆} AVG ≥ α {∆} Data: NDVI by GIMMS, Africa, 1981 August. Resolution: 8km. Smoothed within 1x1 degree. Path: along each longitude (south  north) Interest measure: (Slope) Sameness degree – ∆ : unit slope Thresholds: α= 20% percentile, SD ≥0.5

Potential Project ideas Explore other interest measures to find interesting interval patterns –High correlations time periods between two time series –High variation periods of time series Implement an R software[2] package and enable user defined interest measure [1]. Xun Zhou, Shashi Shekhar, Pradeep Mohan, Stefan Liess, and Peter K. Snyder. "Discovering interesting sub-paths in spatiotemporal datasets: A summary of results." In Proceedings of the 19th ACM SIGSPATIAL International Conference on Advances in Geographic Information Systems, pp ACM, [2]. The R project for statistical computing: