Spawn away from spawn block that was set by /setworldspawn [duplicate]

I am making a custom map and I want to set the world spawn. Whenever use the /setworldspawn command, it never spawns me on the correct block. You will see this at play in this short slide show. First I set the spawn, then I kill myself to check it. As you see in the second photo, I don't spawn on the glass block.

SETTING SPAWN:

SPAWNING:

Does anybody know of an easy way to fix this?

Solution 1:

Try

/gamerule spawnRadius 0

That should spawn you always on the top block in this x and z coordinate. If you want to be spawned underground, you have to use /spawnpoint for all the players that should be affected by it.