How To Change Minecraft Server Seed

Hello, I would like to know how to change my world seed. Our community wants to change things up, hoever we want to keep a portion of our world.

So we used world boarder to trim the world to a 200 block radius, I shut down the server. I changed the seed, but when I get back into the server and go beyond the trim, its loading the old seed. all the old seed landscape is regenerating. It seems that the seed is now held in the world file. How do I change it?

Anyone know a plugin? I've been searching all over the net and this site for terms like "change world seed", "change minecraft server seed", and so on. I cant possibly be the only one that has needed this.

Someone must have come across this?

EDIT by Moderator: merged posts, please use the edit button instead of double posting.

 

"level-seed="

 

Machete.Panda, you could save that portion of the world as a schematic using WorldEdit, then paste that schematic into a new world with whatever seed you wanted, then just smooth out the edges with VoxelSniper or WorldEdit.

 

Yes, I was hoping for a smoother transition.

 

what if you have a macbook pro...