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Hi Sylvain<BR> <BR>The mystery moves to why they didn't 'fix' it in the first place.<BR>I noted that part of the Amazon Basin has a low overall stack-count.<BR>The QA file that follows the geoTiff-data is populated with data (stack-numbers) in the same format (geoTiff) .. that makes it possible to predict troubled areas. I'm not sure if your GIS-tools can incoorporate and use the auxillery-data.<BR> <BR>Carsten<BR>--------------------------------------------------------<br> <BR><div><div id="SkyDrivePlaceholder">Sylvain wrote:</div><div> </div>> Hi Carsten,<br>> <br>> It is almost certain that you are right.<br>> <br>> The chapter "C. Residual Anomalies and Artifacts GDEM" detailed<br>> "Artifacts Related to Stack Number Irregular Boundaries."<br>> - Decripiton of the "pits" is similar to more or less circular holes I<br>> see. The text says they "Regularity and Often Occur with high<br>> frequency in Virtually all ASTER GDEM tiles" and "from just a FEW<br>> meters to 100 meters or more." Ok<br>> - The large positive anomalies similar to "mole run" artifacts (p.23<br>> of the text).<br>> - Undoubtedly the linear artifact are "step anomaly" (p. 19 text).<br>> <br>> Thank you for your comments, I'll put them on the blog to let things clear.<br>> <br>> Bests<br>> <br>> PS: as you assume, unfortunately, no amazon mystery reveled...<br>> <br>> Sylvain<br></div>                                            </div></body>
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