Question Why the area is wrong in OptiSurface? OSD file says that the acreage is 55.03 ha but in reality, it's 5.1 ha. Answer Either of the two below has been selected: You must have accidentally selected feet as the units when you imported.Solution: Import the survey again but select meters as the units. Or, it must have surveyed in feet, and you have imported as meters. Solution: Check the survey file.