Although the practice of remote sensing depends upon the use of accurate field observations, collection of field data remains one of the least systematized aspects of the field. This paper presents a detailed description of the field data collection strategy employed for our study of agricultural land uses in Rondonia, Brazil. Key elements of our approach include: careful positioning of sample areas, multi-image analysis, imagery over several dates, use of video imagery, systematic collection of ground photographs, preparation of detailed maps and field sketches. Field data were carefully examined in the context of these several sources of information, and evaluated to assure that interpretations are consistent with the several sources of data.