Le vendredi 13 mai 2016 14:24:38, Gane R a écrit : > Hi, > > I was working with gdal 2.1.0, I was trying to convert a geopackage raster > to mbtiles, I used GDALCreateCopy to convert the dataset to mbtiles. > > On http://www.gdal.org/frmt_mbtiles.html > > I saw an example to use gdal_translate and then to use gdaladdo to > overviews > > Q1: I got only one level of zoom level in the mbtiles. Is there any > creation option to say to generate mbtiles from a to b zooms ? No. Creation options for MBTILES are documented there : http://gdal.org/frmt_mbtiles.html > or I have to > do by build overviews ??? Yes > > > Q2: I tried to convert the Geopackage ERDC_Whitehorse_GeoPackage.gpkg size > 111 MB in Web Mercator EPSG:3857 from the url > > http://www.geopackage.org/#sampledata > > (GeoPackage contains a raster tile pyramid that was created with free > imagery obtained from Geomatics Yukon and covers an approximately 30 > square-kilometer area centered on the City of Whitehorse. It uses the Web > Mercator (EPSG:3857) coordinate reference system, 256x256 pixel tiles, > contains zoom levels 11-18, and is 110.8MB in size) > > > > *The resulting mbtiles was to 621MB Is this due to default PNG zlevel > settings or any thing can be done on this ?*
The original GPKG probably uses JPEG compression, so if you use -co TILE_FORMAT=JPEG you should get to a similar size. But this will cause some quality loss due to decompression/recompression done in GDAL. You can in a few commands convert a GPKG to MBTiles, provides that it uses a Google Mercator tiling scheme as the sample dataset you use seem to be. Have a look at the procedure described at the end of http://erouault.blogspot.fr/2014/12/gdal-geopackage-raster-support.html Even -- Spatialys - Geospatial professional services http://www.spatialys.com _______________________________________________ gdal-dev mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/gdal-dev
