For a one-year interval, the values in mm/year are exactly equal to mm. Pay attention: velocity is measured as the trend movement, so it does not equal the last minus the first cumulative displacement; instead, it represents the difference in displacement trend. Cumulative displacements are very noisy, and the difference is not informative. That’s why we typically need to display velocities rather than just displacements. For more detailed results, you need to calculate and validate the displacements and trends yourself and detect global, seasonal, and residual trend components using STL or another algorithm, as PyGMTSAR does. As I understand it, StaMPS employs a simpler timeseries filtering approach without the ability to analyze trends and cumulative displacement. In contrast, GMTSAR’s SBAS algorithm can leverage numerous SBAS pairs for a more robust estimation, rather than relying on a single master set of interferograms.
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