The use of the empirical line method to calibrate remotely sensed data to reflectance

To have lasting quantitative value, remotely sensed data must be calibrated to physical units of reflectance. The empirical line method offers a logistically simple means of generating acceptable estimates of surface reflectance. A review and case-study identify the ease with which this method can be applied, but also some of the pitfalls that can be encountered if it is not planned and implemented properly. A number of theoretical assumptions and practical considerations should be taken into account before applying this approach. It is suggested that the empirical line method allows the calibration of remotely sensed data to reflectance with errors of only a few percent.