When Was The Data Collected – Apples vs. Apples

One of the great things about Lidar in coastal areas is the fact that it is collected continually. Most of the coast of the US has multiple (up to 5 or so) dates of collection that we can use to study change. This data can, and often does, cover over a decade of change. In this time, however, the 'typical benchmark' that we get the data in – NAVD 88 – has also gone through its own change. One of the things to be aware of is the Geoid that was used to convert the data from the Ellipsoid it was captured in to the datum we use the most. Check out this article and make sure that you DEMs are apples vs. apples.