<html><body><div style="color:#000; background-color:#fff; font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:16px"><div id="yui_3_16_0_1_1435683765319_3767">Hm. Well the prj is 3857 ...but I reprojected it from 4326....would -<br></div><div id="yui_3_16_0_1_1435683765319_3766"><br></div><div id="yui_3_16_0_1_1435683765319_3583">I did run this on one tile - came out fine:</div><div id="yui_3_16_0_1_1435683765319_4291"><br></div><div id="yui_3_16_0_1_1435683765319_4292" dir="ltr">gdaldem hillshade DCM_N00E116.tif hillshade_test.tif -compute_edges -z 5 -s 111120 -az 90</div><div id="yui_3_16_0_1_1435683765319_4294" dir="ltr"><br></div><div id="yui_3_16_0_1_1435683765319_4297" dir="ltr">but this returned the same result on the global file:</div><div id="yui_3_16_0_1_1435683765319_4298" dir="ltr"><br></div><div id="yui_3_16_0_1_1435683765319_4299" dir="ltr"><br></div><div id="yui_3_16_0_1_1435683765319_4296" dir="ltr">gdaldem hillshade -of GTiff infile_3857.tif hillshade.tif -compute_edges -z 5 -s 111120 -az 90<br></div><div id="yui_3_16_0_1_1435683765319_3582"><br></div><div id="yui_3_16_0_1_1435683765319_3581"><br></div><div id="yui_3_16_0_1_1435683765319_3580"><span></span></div> <br><div class="qtdSeparateBR"><br><br></div><div style="display: block;" class="yahoo_quoted"> <div style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 16px;"> <div style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 16px;"> <div dir="ltr"> <font face="Arial" size="2"> On Tuesday, June 30, 2015 2:41 AM, Even Rouault <even.rouault@spatialys.com> wrote:<br> </font> </div> <br><br> <div class="y_msg_container"><div id="yiv0977550860"><style type="text/css">
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<div style="margin-top:0px;margin-bottom:0px;margin-left:0px;margin-right:0px;text-indent:0px;">Le mardi 30 juin 2015 01:20:13, Ruth Simm a écrit :</div>
<div style="margin-top:0px;margin-bottom:0px;margin-left:0px;margin-right:0px;text-indent:0px;">> I ran this command on a completely NORMAL (but large) global .tiff with a</div>
<div style="margin-top:0px;margin-bottom:0px;margin-left:0px;margin-right:0px;text-indent:0px;">> few tiles missing - but nothing else suspicious - and after 40 minutes it</div>
<div style="margin-top:0px;margin-bottom:0px;margin-left:0px;margin-right:0px;text-indent:0px;">> returned a dud file with '181' being the only value. Has this ever</div>
<div style="margin-top:0px;margin-bottom:0px;margin-left:0px;margin-right:0px;text-indent:0px;">> happened to anyone before?</div>
<div style="margin-top:0px;margin-bottom:0px;margin-left:0px;margin-right:0px;text-indent:0px;">> gdaldem hillshade -of GTiff infile.tif hillshd.tif</div>
<div style="margin-top:0px;margin-bottom:0px;margin-left:0px;margin-right:0px;text-indent:0px;"></div>
<div style="margin-top:0px;margin-bottom:0px;margin-left:0px;margin-right:0px;text-indent:0px;">Ruth,</div>
<div style="margin-top:0px;margin-bottom:0px;margin-left:0px;margin-right:0px;text-indent:0px;"></div>
<div style="margin-top:0px;margin-bottom:0px;margin-left:0px;margin-right:0px;text-indent:0px;">I guess this might be an issue with the ratio of vertical units to horizontal.</div>
<div style="margin-top:0px;margin-bottom:0px;margin-left:0px;margin-right:0px;text-indent:0px;"></div>
<div style="margin-top:0px;margin-bottom:0px;margin-left:0px;margin-right:0px;text-indent:0px;">http://gdal.org/gdaldem.html#gdaldem_hillshade:</div>
<div class="yiv0977550860yqt1228957701" id="yiv0977550860yqtfd11206"><div style="margin-top:0px;margin-bottom:0px;margin-left:0px;margin-right:0px;text-indent:0px;"></div>
</div><div style="margin-top:0px;margin-bottom:0px;margin-left:0px;margin-right:0px;text-indent:0px;"></div><div class="yiv0977550860yqt1228957701" id="yiv0977550860yqtfd00898"><span style="font-weight:600;">-s</span></div> <span style="font-style:italic;">scale</span>:
<div style="margin-top:0px;margin-bottom:0px;margin-left:30px;margin-right:0px;text-indent:0px;">ratio of vertical units to horizontal. If the horizontal unit of the source DEM is degrees (e.g Lat/Long WGS84 projection), you can use scale=111120 if the vertical units are meters (or scale=370400 if they are in feet) </div>
<div style="margin-top:0px;margin-bottom:0px;margin-left:0px;margin-right:0px;text-indent:0px;"></div>
<div style="margin-top:0px;margin-bottom:0px;margin-left:0px;margin-right:0px;text-indent:0px;">I'd suggest you experiment a bit on a subwindow of your big raster or a subsampled version of it first.</div>
<div style="margin-top:0px;margin-bottom:0px;margin-left:0px;margin-right:0px;text-indent:0px;"></div>
<div style="margin-top:0px;margin-bottom:0px;margin-left:0px;margin-right:0px;text-indent:0px;">Even</div>
<div style="margin-top:0px;margin-bottom:0px;margin-left:0px;margin-right:0px;text-indent:0px;"></div>
<div style="margin-top:0px;margin-bottom:0px;margin-left:0px;margin-right:0px;text-indent:0px;">-- </div>
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<div style="margin-top:0px;margin-bottom:0px;margin-left:0px;margin-right:0px;text-indent:0px;">http://www.spatialys.com</div></div></div><br><br></div> </div> </div> </div></div></body></html>