To get this chart, I converted the raw ADC counts to volts, then calculated, based on the circuit design and catalog data for the sensor, the pressure in millibars, and then calculated the altitude in feet using the 1976 Standard Atmosphere. The end points are pretty close: Augusta is in the 1500 foot altitude range and the Touchdown point was 2200 feet or so, so I am pretty confdent that these are valid numbers. Best Regards, Tom  Dawson - WB3AKD