Observer reliability and the validation of remote sensing data

Data gathered by human observers on the ground is essential in validating the interpretation of remote sensing data. Icon-based user interface design for PDA/GPS now makes it possible to gather large quantities of geo-referenced data, even by non-literate observers. However, when there is a discrepancy between the ground-based data and remote sensing data, it can be very expensive to establish the source of the error. To minimize observer error, the design of the PDA/GPS user interface should be simple and self-evident. A reference guide imbedded into the data capture interface will help to validate observations before data is captured. In addition, a rigorous methodology to test the reliability of individual observers will provide metadata essential in validating the reliability of observations.