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5. Differencing DEMs (GCD)

ET-AL Recommendation to IPC

ET-AL recommends using a probabilistic change detection where the error surfaces are those derived using the FIS model, and the recommended confidence interval for thresholding is 95% (for conservative spatial estimates) and 80% for more realistic sediment budgeting purposes.

In this video tutorial we explain how to use GCD project explorer to add a change detection analysis to your GCD Project. Specifically how to perform DoD Analysis with probabilistic thresholding based on a confidence interval.

Your new DEM will always be the current DEM from the most recent survey. Depending on the analysis you wish to conduct, the old DEM can be any of your previous surveys loaded in the project. Typically, you compare the new DEM to the most recent survey, and occasionally to the first (oldest) survey on record.  

GCD 6 - Add Change Probabilistic Thresholding Change Detection To GCD Project

Another useful analysis is to take all your DEM surveys and calculate cell statistics to derive a minimum DEM and a maximum DEM. The Max-Min is another interesting DoD to highlight hotspots of geomorphic change.