the site http://topex.ucsd.edu/cgi-bin/get_srtm30.cgi for SRTM+ 30 sec which contains bathymetry data and http://srtm.csi.cgiar.org/SELECTION/inputCoord.asp for SRTM 3 sec but not contains bathymetry data and http://earth-info.nga.mil/GandG/wgs84/gravitymod/egm2008/first_release.html for DTM2006