That 1 extra area is called Heartlands which is just a green area full of farms and a very small village located inbetween. It's got numerous landmarks on it, but basically it creates some space, removes the verticality and removes the idea that Ponyville is located right below Canterlot's mountain.
The 2nd original team leader behind it wasn't very happy with that decision. There's also a geographic problem with whitetail woods which is located south-west of sweet apple acres yet the teleport is located in the west side and furthermore there's a portal to the left of whitetail woods that leads to the heartlands. That's because the portal was added as an afterthought for farmers to travel faster between heartlands and whitetail woods for the farming patches.


The
https://www.canterlot.com/topic/22652-roleplay-world-overview/