A question from a newcomer:

Does anyone know whether there is any copyright free terrain mapping available for South America with a resolution better than 90m or 3 arc-second?

Google Maps terrain layer would be ideal for the academic publishing need that I have in mind, but their usage guidelines would seem to preclude adding overlays above the original terrain shaded layer.

Matt's Fox's Google Earth LIbrary at www.gelib.com has terrain mapping at 90m or 3 arc-second resolution but whilst it is largely public domain data it would not meet all my needs.

Thanks in advance to anyone who can point me in the right direction.

Martin Coombs