Where to find ocean and earth data maps usable to simulate water depth level?

Question

Searching on USGS I did not find something easily usable without passing from GIS or similar.

I need only something easy to use, like a high map resolution of the Earth without and with ocean. Have you some hint or advice on how to convert available GIS data?

P.S.

Ok, found a starting point, not what I really need but anyway something from which working on

http://www.celestiamotherlode.net/catalog/earth.php

Answer 1

Start by searching for DEMs (Digital Elevation Models). Depending on location, they are available in 30m and occassionally 10m grids. I don't know for sure if they are available for all bathymetric surfaces though.

The files are bascially XYZ points of land surfaces. There are some translation tools available or you could roll your own just for fun.