Prof. Robert Gilmore Pontius Jr
PhD and Professor, Graduate School of Geography, Clark University
Title: "A method to compute land change trajectories in a time series of maps"
Email: rpontius[AT]clarku[Dot]edu
Professor Robert Gilmore Pontius Jr creates quantitative methods that contribute to Geographic Information Science (GIS), Remote Sensing, and Statistics. Pontius is an applied statistician and environmental scientist with expertise in GIS, ecological modeling, and land change science. He has derived mathematical proofs concerning measurements that are essential in various fields. Several of these methods have been incorporated into the GIS & Image Processing software TerrSet, which has over 100,000 users worldwide. His solo-authored book is entitled Metrics That Make a Difference: How to Analyze Change and Error.
Time: 15 or 16 December 2025. 15 minutes of presentation
Abstract:
This webinar presents Trajectory Analysis, which is a novel method to characterize patterns of gross changes during a time series of raster maps. The method computes up to eight trajectories and three components of change: Quantity, Exchange, and Alternation. An application illustrates the concepts by analyzing soybean cultivation during 32 time intervals in western Bahia, Brazil, where Alternation is the largest component of change at temporal resolutions of fewer than 4 years. Readers may apply the timeseriesTrajectories R package available for free at https:// github.com/bilintoh/timeseriesTrajectories. We encourage authors who use our software to contribute to the special issue of described at https://www.mdpi.com/journal/land/special_issues/IND622A7L0.