To calculate density from altitude, temperature, and absolute humidity, one can utilize standard atmospheric tables or refer to NIST's publication on air density equations. The process involves determining the dew point and temperature to find pressure, and using the ideal gas law (PV=nRT) to calculate volume. With known pressure and temperature, specific volume can be derived, which, along with volume, allows for mass calculation. Finally, density can be determined by dividing mass by volume. Understanding these relationships is crucial for accurate density calculations in various applications.