Yes .. it is possible. But not so easy. Anyway it seems we will have to use several data sources anyway. All maps I found use WGS84 and meters for height, so they should go well together. I will test it very soon, since I already have etopo with 2 degree resolution and gtopo30 with 0.5 degree resolution. But gtopo does not have bathymetry ! It also is split into tiles. I have to match the maps and merge them.
With fixed grid where new maps are aligned with the grid variable resolution should be simple.
Good luck I work in GIS company for 7 years now
