Method of milling asphalt

A method of milling asphalt at a design elevation with an asphalt milling machine, the asphalt milling machine having a milling machine body and a rotatable milling drum mounted on a lower portion of the milling machine body, the rotatable milling drum having a bottom surface, the method comprising:

• sensing a relative elevation of an unmilled asphalt pavement surface adjacent to an area to be milled with respect to the milling machine body and rotatable milling drum;
• determining an elevation of the bottom surface of the rotatable milling drum by determining X and Y coordinates of the unmilled pavement surface adjacent to the area to be milled;
• referring to a survey of the unmilled asphalt pavement surface adjacent to the area to be milled, the survey stored in a computer memory, to determine the elevation of the unmilled pavement surface adjacent the area to be milled;
• combining the elevation of the unmilled pavement surface stored in the computer memory with the sensed relative elevation of the unmilled pavement surface;
• and
• based on a map, stored in the computer memory, of a design surface specifying a design elevation of a milled surface over the area to be milled, automatically adjusting the elevation of the milling machine body and the rotatable milling drum such that the rotatable milling drum mills the asphalt surface to the design elevation over the area to be milled.