Replace hardcoded z-level numbers with a trait system

code/game/gamemodes/blob/blob_report.dm

@@ -8,7 +8,7 @@
 	var/mach = 0
 
 /datum/station_state/proc/count()
-	for(var/Z in GLOB.station_z_levels)
+	for(var/Z in SSmapping.levels_by_trait(ZTRAIT_STATION))
 		for(var/turf/T in block(locate(1,1,Z), locate(world.maxx,world.maxy,Z)))
 			// don't count shuttles since they may have just left
 			if(istype(T.loc, /area/shuttle))

code/game/gamemodes/meteor/meteors.dm

@@ -31,7 +31,7 @@ GLOBAL_LIST_INIT(meteorsC, list(/obj/effect/meteor/dust)) //for space dust event
 	var/max_i = 10//number of tries to spawn meteor.
 	while(!isspaceturf(pickedstart))
 		var/startSide = pick(GLOB.cardinals)
-		var/startZ = pick(GLOB.station_z_levels)
+		var/startZ = pick(SSmapping.levels_by_trait(ZTRAIT_STATION))
 		pickedstart = spaceDebrisStartLoc(startSide, startZ)
 		pickedgoal = spaceDebrisFinishLoc(startSide, startZ)
 		max_i--
@@ -40,7 +40,6 @@ GLOBAL_LIST_INIT(meteorsC, list(/obj/effect/meteor/dust)) //for space dust event
 	var/Me = pickweight(meteortypes)
 	var/obj/effect/meteor/M = new Me(pickedstart, pickedgoal)
 	M.dest = pickedgoal
-	M.z_original = M.z
 
 /proc/spaceDebrisStartLoc(startSide, Z)
 	var/starty
@@ -95,7 +94,7 @@ GLOBAL_LIST_INIT(meteorsC, list(/obj/effect/meteor/dust)) //for space dust event
 	pass_flags = PASSTABLE
 	var/heavy = 0
 	var/meteorsound = 'sound/effects/meteorimpact.ogg'
-	var/z_original = ZLEVEL_STATION_PRIMARY
+	var/z_original
 	var/threat = 0 // used for determining which meteors are most interesting
 	var/lifetime = DEFAULT_METEOR_LIFETIME
 	var/timerid = null
@@ -126,6 +125,7 @@ GLOBAL_LIST_INIT(meteorsC, list(/obj/effect/meteor/dust)) //for space dust event
 
 /obj/effect/meteor/Initialize(mapload, target)
 	. = ..()
+	z_original = z
 	GLOB.meteor_list += src
 	SSaugury.register_doom(src, threat)
 	SpinAnimation()

code/game/machinery/computer/camera_advanced.dm

@@ -17,7 +17,7 @@
 /obj/machinery/computer/camera_advanced/Initialize()
 	. = ..()
 	if(station_lock_override)
-		z_lock = GLOB.station_z_levels.Copy()
+		z_lock = SSmapping.levels_by_trait(ZTRAIT_STATION)
 
 /obj/machinery/computer/camera_advanced/syndie
 	icon_keyboard = "syndie_key"

code/game/turfs/simulated/river.dm

@@ -4,7 +4,7 @@
 #define RANDOM_LOWER_X 50
 #define RANDOM_LOWER_Y 50
 
-/proc/spawn_rivers(target_z = ZLEVEL_LAVALAND, nodes = 4, turf_type = /turf/open/lava/smooth/lava_land_surface, whitelist_area = /area/lavaland/surface/outdoors, min_x = RANDOM_LOWER_X, min_y = RANDOM_LOWER_Y, max_x = RANDOM_UPPER_X, max_y = RANDOM_UPPER_Y)
+/proc/spawn_rivers(target_z, nodes = 4, turf_type = /turf/open/lava/smooth/lava_land_surface, whitelist_area = /area/lavaland/surface/outdoors, min_x = RANDOM_LOWER_X, min_y = RANDOM_LOWER_Y, max_x = RANDOM_UPPER_X, max_y = RANDOM_UPPER_Y)
 	var/list/river_nodes = list()
 	var/num_spawned = 0
 	while(num_spawned < nodes)