<div>I think your problem is the incorrect georeferencing of your initial image. I downloaded it from your site:<br> <br><a href="http://www.nebulared.com/tmp_geo/UTM_ED50_Balearic_Island.png">http://www.nebulared.com/tmp_geo/UTM_ED50_Balearic_Island.png</a><br>
<br>loaded it in ArcGIS, gave it coordinate system UTM-30N-ED50 and overlaid boundaries. It becomes obvious that the image is not correctly geo-referenced and it seems that the coordinates in the world file are of the bottom left corner and not top left as it should be. <br>
See the attached jpeg image with printscreens (original and after shifting).<br> <br>Regards<br> <br>Jose' Gonçalves<br> </div>
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<div class="gmail_quote">2008/5/30 Jorge <<a href="mailto:jorge.arevalo@gmail.com">jorge.arevalo@gmail.com</a>>:<br>
<blockquote class="gmail_quote" style="PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0.8ex; BORDER-LEFT: #ccc 1px solid">Now, the results in Google Earth:<br><br>The image before reproyecting (UTM zone 30 datum ED50)<br><a href="http://www.nebulared.com/tmp_geo/Balearic_Island_UTM_ED50.png" target="_blank">http://www.nebulared.com/tmp_geo/Balearic_Island_UTM_ED50.png</a><br>
<br>The image reproyected<br><a href="http://www.nebulared.com/tmp_geo/Balearic_Island_Reprojected.png" target="_blank">http://www.nebulared.com/tmp_geo/Balearic_Island_Reprojected.png</a><br><br>What's the problem?:<br>
- The input image's projection really isn't UTM ED50 (Mapinfo lies??), or is bad georeferenced (low probability...)<br>- The output image's projection really isn't GMaps projection (assuming GMaps projection = GEarth projection)<br>
- GMaps projection not equal GEarth projection (I think so...)<br>- Any other?<br><br>The line executed:<br>gdalwarp -s_srs "+init=epsg:23030 +towgs84=-84,-107,-120,0,0,0,0" -t_srs "+init=epsg:3785 +towgs84=0,0,0,0,0,0,0" -tr 250 250 -co INTERLEAVE=PIXEL Balearic_Island_UTM_ED50.png<br>
Balearic_Island_Reprojected.png<br><br>The epsg codes:<br>Input code (23030):<br># ED50 / UTM zone 30N<br><23030> +proj=utm +zone=30 +ellps=intl +units=m +no_defs <><br><br><br>Output code (3785):<br># Spherical/Web Mercator<br>
<3785> +proj=merc +lat_ts=0.0 +lon_0=0.0 +k=1.0 +x_0=0.0 +y_0=0.0 +a=6378137.0 +b=6378137.0 +units=m +nadgrids=@null +no_defs <><br><br><br>Sorry for the insistence, and thanks a lot<br>Jorge<br><br>Jorge wrote:<br>
<blockquote class="gmail_quote" style="PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0.8ex; BORDER-LEFT: #ccc 1px solid">The EPSG code 3785 is a custom one, but the same of 900913 (I didn't know it thanks), except for the "+wktext" term. What does it mean?<br>
<br>OK, I'm lost with this issue. Could my calcs be wrong? I have, for example, this image:<br><a href="http://www.nebulared.com/tmp_geo/UTM_ED50_Balearic_Island.png" target="_blank">http://www.nebulared.com/tmp_geo/UTM_ED50_Balearic_Island.png</a><br>
<br>And is georeferenced by this world file:<br><a href="http://www.nebulared.com/tmp_geo/UTM_ED50_Balearic_Island.wld" target="_blank">http://www.nebulared.com/tmp_geo/UTM_ED50_Balearic_Island.wld</a><br><br>The image is obtained for a MIF/MID couple of files with UTM projection, zone 30, ED50 datum (Mapinfo said... I don't know what are the dX, dY, dZ parameters, buth they must be -84, -107, -120). Really, the raster file obtained from MIF/MID files isn't a<br>
PNG file, but I did the transform to "see" what I was doing.<br><br>OK, I need to reproject the image, and the output image must be used to overlay it in a GMaps' frame. This is my last attempt:<br><br>gdalwarp -s_srs "+init=epsg:23030 +towgs84=-84,-107,-120,0,0,0,0" -t_srs "+init=epsg:3785 +towgs84=0,0,0,0,0,0,0" -tr 250 250 -co INTERLEAVE=PIXEL UTM_ED50_Balearic_Island.png<br>
GMaps_Balearic_Island.tif<br><br>Then, I transform the TIFF file in a PNG (transformation OK) and I have this image:<br><a href="http://www.nebulared.com/tmp_geo/GMaps_Balearic_Island.png" target="_blank">http://www.nebulared.com/tmp_geo/GMaps_Balearic_Island.png</a><br>
<br>But the image doesn't fit exactly in the map... Is there any error in this reprojection? If the projection is OK, I need to review<br>the rest of the code...<br></blockquote><br>_______________________________________________<br>
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