Great answer from Jukka, just adding abit. With jpg you have to have a world file. One work-around to that is to use tiff or more specifically Gtif/geotif which internally contains the world file/projection info so doesn't need a external world file.
As Jukka explains the gtif way is better than the jpg way of doing things for performance reasons anyway. use gdal_translate to go from source ECW to tif ( geotif ) using the following params -of GTIFF -co TILED=YES -co COMPRESS=JPEG -co PHOTOMETRIC=YCBCR On Thu, Apr 28, 2011 at 7:21 AM, Rahkonen Jukka <jukka.rahko...@mmmtike.fi> wrote: > Hi, > > Jpeg file format is not good for a typical geospatial use when a little > arbitrary piece of a big image should be opened and showed. > > I forgot one tiff creation option, use -co TILED=YES > > That way you can create a tiff image file which is internally organised as > tiles which are fast to fetch without a need to read the whole big image > file. The image data inside tiff can be compressed with jpeg algorithm which > will give the same level of compression than using plain jpeg files. > > When it comes to your original ecw files and the jpeg files you have now in > your hands, forward systematically. > - check the original ecw with gdalinfo > gdalinfo original.ecw > - compare with the gdalinfo or the jpeg file > gdalinfo jpeg.jpg > - you should want to check the tileindex shapefile with some GIS program like > OpenJUMP or QGis; check if the image footprint rectangles are there nice and > if the LOCATION attribute has some reasonable value; consider running > gdaltindex with -write_absolute_path if you are not sure about where the > relative paths will lead > - check the projections in your mapfile, both at MAP and LAYER level > - add DEBUG 5 into your layer and read what you will get into MS_ERRORFILE > - I trust that you will get your images shown and that you will easily find > lots of interesting reading about the topic from the web. > > -Jukka Rahkonen- > > > > > >> -----Alkuperäinen viesti----- >> Lähettäjä: mapserver-users-boun...@lists.osgeo.org >> [mailto:mapserver-users-boun...@lists.osgeo.org] Puolesta >> marten.martinsson >> Lähetetty: 28. huhtikuuta 2011 15:04 >> Vastaanottaja: mapserver-users@lists.osgeo.org >> Aihe: [mapserver-users] Re: JPG Tile index in mapserver v5.6.3 >> >> Hi Jukka! >> >> I already tried to change the file ending on the world file >> but it didn´t >> help. >> >> Not really with you on yor 2nd tip there. >> >> You want me to convert the jpg to tiff-files instead? >> I am pretty new to GDAL so could you explain what the >> functions actually >> does? >> >> /M >> >> >> >> -- >> View this message in context: >> http://osgeo-org.1803224.n2.nabble.com/JPG-Tile-index-in-mapse > rver-v5-6-3-tp6312908p6312963.html >> Sent from the Mapserver - User mailing list archive at Nabble.com. >> _______________________________________________ >> mapserver-users mailing list >> mapserver-users@lists.osgeo.org >> http://lists.osgeo.org/mailman/listinfo/mapserver-users >> > _______________________________________________ > mapserver-users mailing list > mapserver-users@lists.osgeo.org > http://lists.osgeo.org/mailman/listinfo/mapserver-users > _______________________________________________ mapserver-users mailing list mapserver-users@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/mapserver-users
