How is fieldwork used to improve thematic classification?
There is no such thing as armchair geography. Reality is the best test for land cover accuracy. Fieldwork gives the analyst a critical view and feel for the landscape in a holistic sense that is not possible from aerial photography and other traditional methods of accuracy assessment. The C-CAP approach to fieldwork provides two means of assessing accuracy, statistical, and fitness for use. In traditional methods of field verification, a paper map was used, and a random point was plotted, navigated to, and observed. Under this procedure, the observation of 30 sites per day per team was considered a strong success. Another option is a “windshield survey” approach. This is a biased system in which observers simply note what they can observe from transportation routes. This method provides for more observations, but without statistically valid random sampling. Both systems have their individual advantages and problems.
