In a method and system for measuring wear in the lining of a vessel by a laser contouring system having an electromagnetic radiation emitting and receiving device. The laser contouring system references permanent marks and temporary marks positioned outside, on, or within the vessel. The distances and direction from the electromagnetic radiation emitting and receiving device to the fixed and temporary marks is determined during an initial measurement by the electromagnetic radiation emitting and receiving device from a first scanning position. The electromagnetic radiation emitting and receiving device is then moved along a path from the first scanning position to a second scanning position wherein some of the marks which were scanned from the first scanning position are scanned again to determine the relative position of the vessel and points on the internal lining of the vessel to determine the contour of the lining.