In the Sahara, the river-based system is naturally of little use. Korandje instead preserves the east-west axis, using the same structure as mainstream Songhay varieties: inə̣w n ṭʕạ-yu "east" ("sunrise"), inə̣w n yạṛaħ-yu "west" ("sunset"). This is not, however, accompanied by any fixed north-south axis; for "north", elicitation sometimes yields bəlhadi, properly "the North Star", but this term is not used to describe locations in the way that "east" and "west" are, and there seems to be no proper equivalent to "south". I'm tempted to suggest that this reflects the oasis' general reluctance to think about its historic southern ties, but in a way it maps on to another, better-established three-direction coordinate system used in Tabelbala. The latter is not perpendicular, and not in my limited experience ever used for describing locations; rather, it relates to the wind directions.
In the rest of Northern Songhay, spoken in and around the Azawagh Valley - as far as I gather from secondary sources - the relevant vocabulary is largely Tuareg-derived, with no attested Songhay survivals. Tagdal, spoken by the largely nomadic Igdalen, has borrowed the system whole from (Tawellemmet) Tamajeq: "west" is ataram, "east" dinnik, "south" ággaala, "north" támmasna. (Among these, "north" is originally a toponym, "desert".) Tasawaq, spoken in the oasis of In-Gall, differs only in the name for "east": alkubla (from Arabic alqiblah "direction of prayer"). Emghedesie, the extinct variety of the town of Agades, agrees with Tasawaq on "east" and "west", but uses toponyms for "north" and south", respectively air (ie the Air Mountains) and asudán (Arabic as-sūdān "(land of the) Blacks"). (Note, however, that Tayart Tamajeq too uses ayəṛ for "north".) I have no data on Tadaksahak directions for the moment.
|E||inə̣w n ṭʕạ-yu||elkúbla||alkúbla||dinnik|
|W||inə̣w n yạṛaħ-yu||atáram||átáram||ataram|