There has been a marked growth in the number of spacecraft and airborne sensors since 1972, the date of the launching of the first satellite developed to monitor Earth's resources (LANDSAT). As a consequence, geographers interested in remote Sensing in New Zealand have had a widening range of data sources available to them. Geographers first expressed interest in monitoring ground cover using I.ANDSAT series data, but interest in remote sensing data has widened to include work on marine environments, structural geology, urban areas and soil survey. As Curran (1984) indicates, the development and use of thermal and microwave sensors is likely to rapidly extend the uses of remote sensing. In New Zealand, the growth in the number of stored data bases plus the increased sophistication of digital computer analysis (both dominated by the national centre, The Remote Sensing Section. DS1R) is encouraging. However, it is a matter of some concern that there does not seem to be a parallel growth in the radiometric field work required to reconcile sensor data with field information. This note examines some of the reasons which have led to this problem, stresses the importance of radiometric ground truth and describes a method of collecting radiometric data which is in operation at the University of Waikato.