The nomos of the post-city forms specific phenomenologies of spatial development that go beyond the classical interpretations of the concepts of the biosphere and the noosphere. The ontology of planetarity is based on the spatial “inclusiveness” of any planetary object due to its specific localization, determined both by planetary conditions and the co-spatiality of the planet within the intelligible and explored cosmos. Post-urban co–spatialities are the ontological “base” for the emergence of specific terrestrial planetarities of special intensity. A post-city can be a topos of terrestrial planetariums becoming trans-planetary, first in metaphysical and then in physical relations. Post-urban trans-planetarity is the relativity of multiple imaginative cartographies representing the corresponding meta-geographies. Planetary post-urbanism is formed as coexisting planetary cartographies of the imagination, self-organizing into meta-cartography and relying on appropriate communicative co-spatialities. Trans-planetary post-urban geo-cultures in “cloning” local symbolic codes associated with the Earth include them in new cartographies of the imagination in co-spatial extraterrestrial loci. The co-spatialities of human communities become divided during the transitions from artificial internal environments to external trans-planetary environments that are not related to terrestrial geo-cultures. Post-urbanism, in contributing to the expansion of ambivalent networks of presence/absence cartographies, creates new opportunities for the ontological intensification of space-as-a-relationship, allowing post-urban human communities to think and act trans-planetarily. “Rhizomatic” post-nomadism makes or re-creates the Earth in the ontological sense as a giant cosmic “desire machine”. Fragments of trans-planetary post-urban noospheres will be understood as organic and autonomous geo-cultures, representing communicative fractals, whose placement can be considered as a kind of cosmo-geopolitics.