The TIROS-N/NOAA-A, -J series of meteorological satellites transmit imagery data to the Earth in both digital and analogue formats. The analogue data are a processed subset of the digital data and have lower resolution. A quantitative evaluation of a post-reception digitized version of this is made using the corresponding digital data as a standard. In nine comparisons the calibration of the infrared sensor on board was within 001°C. Sea surface temperature estimates from APT data were 0.3°C below the corresponding digitally transmitted data. The albedo estimates were within 0.2 per cent. Processed APT data are adequate for many mesoscale measurements in the fields of oceanography and meteorology and are more readily accessible than the digitally transmitted data.