According to the present invention, a method and a device for determining a physical quantity at a plurality of locations are provided. The method according to the invention comprises approaching the plurality of locations in a first predetermined direction, wherein at each location of the plurality of locations a first measured value of the physical quantity is measured, approaching the plurality of locations in a second predetermined direction substantially opposite to the first predetermined direction, wherein at each location of the plurality of locations a second measured value of the physical quantity is measured, and establishing a determination value for the physical quantity at a respective location of the plurality of locations based on the first and second measured values of the physical quantity which have been measured at the respective location.