Hi, I'm working on aster images in order to extract dem. The dem extraction module is really fast and easy to use, but maybe my poor knowledge in the core of the process, result in a noisy output dem image. I used the maximum level (5), and a minimum correlation of .8 At a first look the dem is good, but there is a sort of granule noise with a z variation of 5 to 7 meters. Yes, I can use a filter routine but....: is a normal output the one I obtained? (please, see a subsubset of the image at http://192.167.121.83/download/asterdem.jpg - the noise is not a jpeg artifact) do exist some particular setting to avoid this effect? wich is the best filtering process to obtain a good (i.e. both natural and correct) DEM? thank you very much antonio zeoli