<HTML><BODY style="word-wrap: break-word; -khtml-nbsp-mode: space; -khtml-line-break: after-white-space; "><BR><DIV><DIV>On Jun 2, 2006, at 7:13 AM, Lennox Antoine wrote:</DIV><BR class="Apple-interchange-newline"><BLOCKQUOTE type="cite"><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">I believe this is the same projection used in VirtualEarth</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">(<A href="http://local.live.com/default.aspx?v=2&cp=0~0&style=h&lvl=1&scene=1875974">http://local.live.com/default.aspx?v=2&cp=0~0&style=h&lvl=1&scene=1875974</A>),</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">so you can check out the projection they used to get it into</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">Geographic LL coordinates.</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><A href="http://www.brains-n-brawn.com/default.aspx?vDir=veworldwind">http://www.brains-n-brawn.com/default.aspx?vDir=veworldwind</A></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">I'll paste the reprojection area of the code here :</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">//NOTE tiles did not line up properly with ellps=WGS84</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">//string [] projectionParameters = new string[]{"proj=merc",</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">"ellps=WGS84", "no.defs"};</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">//+proj=longlat +ellps=sphere +a=6370997.0 +es=0.0</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">string [] projectionParameters = new string[]{"proj=merc",</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">"ellps=sphere", "a=" + earthRadius.ToString(), "es=0.0", "no.defs"};</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">proj = new Projection(projectionParameters);</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">I have also had luck estimating it with tangent and log functions</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">without using proj.4.</DIV></BLOCKQUOTE></DIV><BR class="khtml-block-placeholder"><DIV>Hi Lennox, thanks for the response.</DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV>I'm not sure how to turn what you've given me into command line parameters for gdalwarp or gdaltranslate tho... The Mercator projection string sounds pretty similar to what I was trying before...</DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV>1) Save <FONT class="Apple-style-span" color="#002FD7"><SPAN class="Apple-style-span" style="text-decoration: underline;"><A href="http://veimages.gsfc.nasa.gov/7107/world.topo.bathy.200408.3x5400x2700.jpg">http://veimages.gsfc.nasa.gov/7107/world.topo.bathy.200408.3x5400x2700.jpg</A></SPAN></FONT> as world.jpg..</DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV>2) gdal_translate -a_srs EPSG:32662 -gcp 0 0 -180 90 -gcp 5400 0 180 90 -gcp 5400 2700 180 -90 world.jpg world.tif</DIV><BLOCKQUOTE type="cite"></BLOCKQUOTE><DIV><BR class="khtml-block-placeholder"></DIV><DIV>3) gdalwarp -s_srs EPSG:32662 -t_srs "+proj=merc +datum=WGS84" -ts 512 512 world.tif worldm.tif</DIV><BLOCKQUOTE type="cite"></BLOCKQUOTE><BR><DIV>(EPSG:32662 is the projection code for WGS84 Plate Carree)</DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV>So are you suggesting I add "+ellps=sphere", "es=0" and "+a=earthRadius" to my gdalwarp command?</DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV>-robert</DIV></BODY></HTML>