EXTRACT XYZ GRID OF TOPOGRAPHY
Extract topography from global 30 arcsecond grid in ASCII XYZ-format - SRTM30_PLUS V9.0.
Enter data window.
These files can get quite large so you may have to divide the area up into smaller chunks.
Reference: Becker, J. J., D. T. Sandwell, W. H. F. Smith, J. Braud, B. Binder, J. Depner, D. Fabre, J. Factor, S. Ingalls, S-H. Kim, R. Ladner, K. Marks, S. Nelson, A. Pharaoh, R. Trimmer, J. Von Rosenberg, G. Wallace, P. Weatherall., Global Bathymetry and Elevation Data at 30 Arc Seconds Resolution: SRTM30_PLUS, Marine Geodesy, 32:4, 355-371, 2009.
Global Topography SRTM30_PLUS
Marine Gravity from Satellite Altimetry
SATELLITE GEODESY homepage