<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_1435684912142_3252"><span id="yui_3_16_0_1_1435684912142_3320">Yup. That's why I thought...so back to square one....</span></div><div id="yui_3_16_0_1_1435684912142_3252"><span><br></span></div><div id="yui_3_16_0_1_1435684912142_3252"><span id="yui_3_16_0_1_1435684912142_3593">Why do I get a dud file with:</span></div><div id="yui_3_16_0_1_1435684912142_3252"><span><br></span></div><div id="yui_3_16_0_1_1435684912142_3252" dir="ltr">gdaldem hillshade -of GTiff infile.tif hillshd.tif<span><br></span></div> <div id="yui_3_16_0_1_1435684912142_3252" class=""><span class=""><br class=""></span></div><br><div class="qtdSeparateBR"><br><br></div><div class="yahoo_quoted" style="display: block;"> <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 size="2" face="Arial"> On Tuesday, June 30, 2015 10:07 AM, Even Rouault <even.rouault@spatialys.com> wrote:<br> </font> </div> <br><br> <div class="y_msg_container">Le mardi 30 juin 2015 19:05:58, Ruth Simm a écrit :<br clear="none">> Hm. Well the prj is 3857 ...but I reprojected it from 4326....would -<br clear="none">> <br clear="none">> I did run this on one tile - came out fine:<br clear="none">> gdaldem hillshade DCM_N00E116.tif hillshade_test.tif -compute_edges -z 5 -s<br clear="none">> 111120 -az 90 but this returned the same result on the global file:<br clear="none">> <br clear="none">> gdaldem hillshade -of GTiff infile_3857.tif hillshade.tif -compute_edges -z<br clear="none">> 5 -s 111120 -az 90<br clear="none"><br clear="none">For EPSG:3857, you shouldn't add -s 111120 as the horizontal units are <br clear="none">already meters.<br clear="none"><br clear="none">> <br clear="none">> <br clear="none">> <br clear="none">> <br clear="none">> <br clear="none">> On Tuesday, June 30, 2015 2:41 AM, Even Rouault<br clear="none">> <<a shape="rect" ymailto="mailto:even.rouault@spatialys.com" href="mailto:even.rouault@spatialys.com">even.rouault@spatialys.com</a>> wrote:<br clear="none">> <br clear="none">> <br clear="none">> #yiv0977550860 p, #yiv0977550860 li {white-space:pre-wrap;}Le mardi 30<br clear="none">> juin 2015 01:20:13, Ruth Simm a écrit :> I ran this command on a<br clear="none">> completely NORMAL (but large) global .tiff with a> few tiles missing - but<br clear="none">> nothing else suspicious - and after 40 minutes it> returned a dud file<br clear="none">> with '181' being the only value. Has this ever> happened to anyone<br clear="none">> before?> gdaldem hillshade -of GTiff infile.tif hillshd.tifRuth,I guess<br clear="none">> this might be an issue with the ratio of vertical units to<br clear="none">> horizontal.http://gdal.org/gdaldem.html#gdaldem_hillshade:-s scale:ratio<br clear="none">> of vertical units to horizontal. If the horizontal unit of the source DEM<br clear="none">> is degrees (e.g Lat/Long WGS84 projection), you can use scale=111120 if<br clear="none">> the vertical units are meters (or scale=370400 if they are in feet) I'd<br clear="none">> suggest you experiment a bit on a subwindow of your big raster or a<br clear="none">> subsampled version of it first.Even-- Spatialys - Geospatial professional<br clear="none">> serviceshttp://www.spatialys.com<div class="yqt5891234478" id="yqtfd49571"><br clear="none"><br clear="none">-- <br clear="none">Spatialys - Geospatial professional services<br clear="none"><a shape="rect" href="http://www.spatialys.com/" target="_blank">http://www.spatialys.com</a></div><br><br></div> </div> </div> </div></div></body></html>