Abstract: A pressure measurement device with a selective altitude threshold crossings accumulator and method therefor provides for selective accumulation of relative pressure thresholds. A pressure sensor measures atmospheric pressure and provides analog pressure signals representing measured atmospheric pressures. A digital-to-analog converter converts the analog pressure signals to digital pressure signals for a computer which then computes altitudes corresponding to the measured atmospheric pressures. The computer assigns a threshold flag value which corresponds to the relative direction (e.g. "up" or "down") from a first (e.g. lower) altitude to a second (e.g. higher) altitude when the magnitude of the first-to-second altitude differential exceeds a first threshold. The computer then generates a unit count when both the relative direction from the second altitude to a third (e.g.