The European Space Agency has added Envisat Advanced Synthetic Aperture Radar (ASAR) to the MIRAVI image rapid visualisation service. MIRAVI is free and open access and allows users to download full resolution MERIS (optical-infrared) and ASAR imagery in Bitmap (bmp) and JPEG (jpg) format. The images are high resolution and can exceed 100 Mb (e.g. for a MERIS bmp image).
The use of JPEG and Bitmap formats means the data are 8-bit, and are therefore somewhat limited in their usefulness. Quantiative image comparisons are not recommended. There are plenty of applications for which these data could prove useful: mapping features such as lake areas or geomorphology, for example. Perhaps most importantly, in releasing these data ESA is taking a big step in the right direction: towards a more open data policy.