Gravity
- Global Gravity Field Models from International Centre for Global Earth Models: http://icgem.gfz-potsdam.de/ICGEM/modelstab.html
- Gravity equations information page from Geological Survey of Canada: http://gsc.nrcan.gc.ca/gravity/formulae_e.php
- Global Topography/Bathimetry Models from NOAA's National Geophysical Data Center: