This section starts with a presentation of the NOAA-AVHRR earth observation system, and of the formats in which the data are transmitted and distributed. Then follows a description of the SPACE software, with emphasis on the latest version called SpacePC. The general concepts of the software are outlined by means of flowcharts and tables, while the spatial and radiometric algorithms are further detailed in separate paragraphs. In the meantime, some attention is paid to the historical development and practical uses of the software. Within the scope of this document, it’s impossible to describe all the technical details of the system. For a more in-depth discussion we refer to Piccard et al. (2002b) and to the sources mentioned in the reference chapter.