How can the error of the gyro compass be determined?

The error of a gyro compass can be determined by comparing its indicated heading with a known reference, such as a magnetic compass or celestial navigation. This involves taking readings from both instruments under stable conditions and noting any discrepancies. Additionally, the gyro compass error can be assessed by performing calibration procedures, which may include adjusting for factors like latitude and ship's speed. Regular checks and adjustments help ensure accurate heading readings and minimize error.