Good point. If I retrofit the term "resolution" in place of "velocity", the author's statement does make a lot more sense. If that's what was intended they real

Good point. If I retrofit the term "resolution" in place of "velocity", the author's statement does make a lot more sense. If that's what was intended they really should have used that terminology, because I was similarly confused at the term "velocity." Whenever I've worked with time series data I've always referred to the granularity of the time dimension as its "resolution" - this is also common in geospatial data. I don't think (but am happy to be corrected) that "velocity" is a term of art in timeseries analysis.