Surveyor's Map in Agricola Farmers of the Moor
As far as I know there is no official ruling on this. However, most people seem to agree that the field should still obey the general rule for placing fields, i.e. it needs to be placed orthogonal to an existing field. This is for example the ruling for Surveyor's Map on page 28 of the unofficial Agricola compendium:


  Surveyor's Map M018
  
  Place a field tile on the space for round 11, a moor tile on round 12, and a forest tile > on round 13. At the start of the rounds, you must either place the tile on an empty space in your farm or return it to the supply.
  
  => Placing the field tile does not count as a ploughing action.
  
  => If you already have fields, you must place the field tile adjacent to an existing field.