Ciao Juanita, png is bad for serving, that is as an input format. Geotiff is much more powerful.
As an output format for WMS is reasonably good, especially when there is transparency in the mix. Regards, Simone Giannecchini ------------------------------------------------------- Ing. Simone Giannecchini GeoSolutions S.A.S. Founder Via Poggio alle Viti 1187 55054 Massarosa (LU) Italy phone: +39 0584 962313 fax: +39 0584 962313 mob: +39 333 8128928 http://www.geo-solutions.it http://geo-solutions.blogspot.com/ http://www.youtube.com/user/GeoSolutionsIT http://www.linkedin.com/in/simonegiannecchini http://twitter.com/simogeo ------------------------------------------------------- On Fri, Feb 4, 2011 at 4:27 PM, Juanita Dahlin <juanita...@gmail.com> wrote: > Dear Simone, > > Thanks so much for your help. The video was very helpful! I will try the > gdalwarp command that you recommended with the full set of .tif images and > see how that works. > > I am curious as to why .png files are not recommended for GIS? The Layer > Preview OpenLayers calls return .png format and the ImageMosaic example that > comes with GeoServer uses .png as well. Is this just because the .png format > does not support ge-referencing within the file itself? > > Grazie Mille, > Juanita Dahlin > > On Fri, Feb 4, 2011 at 3:26 AM, Simone Giannecchini > <simone.giannecch...@geo-solutions.it> wrote: >> >> Ciao Juanita, >> please, read my comments below... >> >> Simone >> ------------------------------------------------------- >> Ing. Simone Giannecchini >> GeoSolutions S.A.S. >> Founder >> >> Via Poggio alle Viti 1187 >> 55054 Massarosa (LU) >> Italy >> >> phone: +39 0584962313 >> fax: +39 0584962313 >> mob: +39 333 8128928 >> >> >> http://www.geo-solutions.it >> http://geo-solutions.blogspot.com/ >> http://www.linkedin.com/in/simonegiannecchini >> http://twitter.com/simogeo >> >> ------------------------------------------------------- >> >> >> >> On Thu, Feb 3, 2011 at 5:27 PM, Juanita Avila <juanita...@gmail.com> >> wrote: >> > I've had all sorts of trouble getting GeoServer 2.0.2 to create an >> > ImageMosaic from GeoTIFF files. No matter what I try I get this error: >> > >> > Could not list layers for this store, an error occurred retrieving them: >> > Unable to acquire a reader for this coverage with format: ImageMosaic >> > >> > I finally managed to create an ImageMosaic by taking a hint from the >> > mosaic_sample that ships with GeoServer and converting my GeoTIFF files >> > to >> > PNGs, but I don't feel that this is an ideal solution. >> > >> > I suspect that the GeoServer GeoTIFF reader is not quite compatible with >> > the GeoTIFF files that I'm using, even though I've tried all sorts of >> > conversion tools including gdalwarp, Erdas ViewFinder. I've even >> > followed >> > the old instructions for manually generating shape information with >> > gdaltindex. >> > >> > The images that I'm attempting to mosaic are publically available at >> > this >> > site: >> > >> > >> > http://aeronav.faa.gov/index.asp?xml=aeronav/applications/VFR/chartlist_sect >> > >> > Notice that each image also comes with a world file (.tfw) and an HTML >> > text >> > description. >> > >> >> These geotiff files do not have a proper EPSG code, GeoServer requires >> it in order >> to publish them. >> >> >> > These files are somewhat problematic to mosaic in their native state >> > because >> > each has it's own localized projection. However, I found that I easily >> > could >> > reproject the files to EPSG:4326 (WGS 84) with both Erdas ViewFinder and >> > gdalwarp. >> > >> >> You should not reproject each of them separately, you should try to >> merge them first (look at gdal_merge for this) >> otherwise you can use gdal_warp and warp all of them at the same time. >> If you don't do this you'll get all sort of >> side effects (i.e. black collar) at the edges. >> >> > In fact, I also had trouble creating a simple GeoTIFF store/layer from >> > just >> > one of these files until I removed the .tif extension from the file. >> > Once I >> > did that, GeoServer had no trouble processing the image! >> >> Honestly I have no idea what you are talking about here. >> >> > GeoServer could not >> > determine projection information unless I reprojected the files to >> > EPSG:4326 >> > first, but it did load the files either way, so long at the .tif >> > extension >> > was removed. I also tried .tiff, .geotiff, .TIF, .TIFF, and .GeoTIFF; >> > but >> > the only method that worked was no extension at all! >> > >> >> Same as above for the extension of the files. As far as the projection >> is concerned, geoserver >> sees the projection but it needs a proper epsg code which we do not >> have for these files. >> >> >> > Let's consider creating a simple mosaic with just 2 images that are >> > right >> > next to each other on a map of the earth: >> > >> > Chicago 81 North.tif >> > Detroit 81 North.tif >> > >> > The projection information for each of these files is identical (NAD83 , >> > EPS:4269) except for the "latitude of origin": >> > >> > Chicago: "latitude_of_origin",42.66666666666666 >> > Detroit: "latitude_of_origin",42.1 >> > >> > The tif files also reference the .tfw files. >> > >> > gdalwarp -t_srs EPSG:4326 "Chicago 81 North.tif" >> > 4326_chicago_81_north.tif >> > gdalwarp -t_srs EPSG:4326 "Detroit 81 North.tif" >> > 4326_detroit_81_north.tif >> > >> > After these conversions, the GeoTIFF files no longer reference the tfw >> > files >> > and the tif files share the exact same projection: >> > >> > GEOGCS["WGS 84", >> > DATUM["WGS_1984", >> > SPHEROID["WGS 84",6378137,298.257223563, >> > AUTHORITY["EPSG","7030"]], >> > AUTHORITY["EPSG","6326"]], >> > PRIMEM["Greenwich",0], >> > UNIT["degree",0.0174532925199433], >> > AUTHORITY["EPSG","4326"]] >> > >> > By copying them to a new chic_det_test directory under the geoserver >> > coverages directory, I can try to create a new ImageMosaic store: >> > Data Source Name: chic_det_test >> > URL: file:coverages/chic_det_test >> > >> > I always see my favorite error, even if I remove the .tif extensions >> > from >> > the files: >> > >> > Could not list layers for this store, an error occurred retrieving them: >> > Unable to acquire a reader for this coverage with format: ImageMosaic >> > >> > A survey of the geoserver.log file provides no additional information on >> > the >> > cause of the problem: >> > >> > 2011-02-03 10:57:50,343 INFO [geoserver.web] - Getting list of coverages >> > for >> > saved store file:coverages/chic_det_test >> > java.lang.RuntimeException: Could not list layers for this store, an >> > error >> > occurred retrieving them: Unable to acquire a reader for this coverage >> > with >> > format: ImageMosaic >> > >> > The Erdas ViewFinder method is similar. I open the files in that GUI >> > tool, choose to save as TIFF, with the following Output File Options: >> > Change Output Pixel Size to Degrees >> > Change Output Projection to Category: Geographic and Projection: Lat/Lon >> > (WGS 84) >> > Resample Method: Nearest Neighbor >> > >> > Erdas ViewFinder produces a .tfw AND an .aux file, which are both >> > referenced >> > in the .tif file, so I copy the .tif, .tfw, and .aux files to a new >> > erdas_chic_det_test folder under geoserver coverages and try again. >> > Data Source Name: erdas_chic_det_test >> > URL: file:coverages/erdas_chic_det_test >> > >> > Same error! >> > >> >> What you did below is not recommended. Png is a bad format for generic >> gis serving. >> >> Here (http://www.youtube.com/user/GeoSolutionsIT#p/a/u/0/X74LH9bDuek) >> is a video that shows what I did in my tests. I used a snapshot for >> geoserver 2.0.x taken from here: >> >> http://geoserver.org/display/GEOS/Nightly >> >> 2.0.x is stable hence you can use it. >> >> Simone. >> >> > I finally got smart and renamed the .tfw files to .pgw files, grabbed >> > the >> > projection information the .tif files and created a .prj for each tif, >> > then >> > opened the tifs in an image editing tool and saved as .png. At least the >> > image editing allowed me to strip off the legend information (which we >> > really do not want to display on map of the earth). >> > >> > That did the trick, but it's not a great solution. These maps are >> > regularly >> > updated, so we'll need to follow this process every couple months to >> > keep >> > our site up to date. >> > >> > If you have any other recommendations, I'd be very grateful! >> > >> > Thanks for your help, >> > Juanita Dahlin >> > >> > ------------------------------------------------------------------------------ >> > Special Offer-- Download ArcSight Logger for FREE (a $49 USD value)! >> > Finally, a world-class log management solution at an even better >> > price-free! >> > Download using promo code Free_Logger_4_Dev2Dev. Offer expires >> > February 28th, so secure your free ArcSight Logger TODAY! >> > http://p.sf.net/sfu/arcsight-sfd2d >> > _______________________________________________ >> > Geoserver-users mailing list >> > Geoserver-users@lists.sourceforge.net >> > https://lists.sourceforge.net/lists/listinfo/geoserver-users >> > >> > > > > ------------------------------------------------------------------------------ > The modern datacenter depends on network connectivity to access resources > and provide services. The best practices for maximizing a physical server's > connectivity to a physical network are well understood - see how these > rules translate into the virtual world? > http://p.sf.net/sfu/oracle-sfdevnlfb > _______________________________________________ > Geoserver-users mailing list > Geoserver-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/geoserver-users > > ------------------------------------------------------------------------------ The modern datacenter depends on network connectivity to access resources and provide services. The best practices for maximizing a physical server's connectivity to a physical network are well understood - see how these rules translate into the virtual world? http://p.sf.net/sfu/oracle-sfdevnlfb _______________________________________________ Geoserver-users mailing list Geoserver-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/geoserver-users
