Is there a word for depth-based like spatial is for space?

Solution 1:

You might find suitable the following construction by means of the suffix "-wise"; it yields several well established terms, but is as well endowed with the characteristic of being freely productive.

-wise (Shorter OED) Forming a) advs. and adjs. chiefly from ns. w the sense '(that is) in the manner, form or direction of' as crosswise, latticewise, otherwise, b) advs. from ns. w the sense 'as regards, in terms of' as pairwise, plotwise'now freely productive in the formation of nonce-words as employment-wise, moneywise, publicity-wise, etc.).

• depthwise

You dispose here of 111 examples to get a feel of this word, which is in fact an existant, freely produced word (that is, not in the dictionaries (yet)).