I just wanted to give you guys who hsnt figured it out a guide.
I will update this thread the more ways i can figure out.
-[Changing the sieze of an map]-
1. save the map by simply pressing the button that says "save" when opened / editing the map.
2. go to your "sketches" folder , usally located in C:\Users\User\AppData\Roaming\PlaneShift [Thats my location , im using windows 7]
3. Open the name-of-map.xml with an program like notepad [or a xml editing program if you have 1, i recomend Peter's Xml Editor , it's a freeware , just google to find it]
4. then simply change the " w="0" h="0" , it's simply Height and Width, this will save into the game , and it will show the same siese for other players too , enjoy ^^
[Other Links]
Here is a website that i strongly reccomend if you want to go deeper into the art of XML editing
http://www.w3schools.com/Register, read forums, etc.
Enjoy!