Quote Victor_D (

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First of all, I am sorry if this has been discussed before.
That's what the search function is for! Surface landscapes on Oceania planets is a known bug:
http://en.spaceengine.org/forum/4-1946-1#34496
As to the possible types of Oceania, some may simply be terrestrials like Earth but with more Ocean (your type a), and others may be completely water worlds, with transitions to high-pressure ices at lower levels (type b). From above these may superficially look the same, but some properties like bulk density will be different. I don't know if SE yet distinguishes the different types, but it is supposed to render them as a terrestrial sized body with a deep ocean. Some may also have ice caps or a frozen surface like Europa, depending on distance, rotation, and greenhouse effect.