1	Gravity, Geoids, and Other Vertical Datums in the Puerto Rico/Virgin Islands Region Dr. Daniel R. Roman and Dr. Yan Ming Wang
2	Significant Concepts & Terms Geodetic Ellipsoidal Height and/or Datum (h) Geodetic or Orthometric Height and/or Datum (H) Geoid Height (N) h = H + N The geoid and gravity anomalies are related mathematically: Oceanographic Global Mean Sea Level (MSL) Local MSL (LMSL) or Local Mean Tide Mean Dynamic Topography (MDT) MSL + MDT = LMSL MSL => Geodetic Datum LMSL => Local Vertical Datum
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12	Statistical Comparison Between Available Geoid Height Models and 13-Point GPS on BM Profile Along NW Puerto Rico Shoreline
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19	Available Elevation Data Sets
20	Conclusions Tidal and Geodetic datums are related Additional gravity data are required Geoid modeling is best constrained with additional oceanic gravity observations Some limited terrestrial observations will help fill in gapped regions but also help to eliminate any datum problems
21	Outlook Improved terrain models already exist to help model the shortest wavelengths Simultaneous lidar observations would help to model the local sea surface and any implied datum shifts Impending satellite gravity missions aid in resolving global mean sea level A future gravimetric geoid can be generated that will cover CONUS & PR/VI