Le jeudi 12 novembre 2015 18:02:59, Alex M a écrit : > The spatialite db contains spatial reference tables of projections. > Thats where those MB come from.
I confirm. Spatialite by defaults populates the spatial_ref_sys table with all the EPSG catalog (but you can actually remove all the ones you don't use and do a VACUUM to shrink the file. And through the InitSpatialMetaData() SQL function you can also decide to have an empty table or just with EPSG:4326), whereas in GeoPackage you only have 3 mantatory SRS (undefined geographic, undefined projected and EPSG:4326) + the other ones you actually used. Spatialite has also a few extra metadata tables, but their inpact on the file size should be neglectable. > As Andrea pointed out the full answer of > what else is in those MB would be on the Spatialite mailing list. > > -Alex > > On 11/12/2015 08:49 AM, Andrea Peri wrote: > > You need study better the spatialite formats. > > > > :) > > > > Also the shapefile format and also the geopackage format. > > So you will be able to understand why spatialite is 4mb and other not. > > > > :)) > > > > A. > > > > 2015-11-12 17:34 GMT+01:00 Bernd Vogelgesang <[email protected]>: > >> Am 12.11.2015, 16:17 Uhr, schrieb Paulo van Breugel > >> <[email protected]>: > >> > >> > >> > >> On Thu, Nov 12, 2015 at 3:48 PM, Neumann, Andreas <[email protected]> > >> > >> wrote: > >>> I believe the main difference between SpatiaLite and Geopackage is that > >>> a SpatiaLite database contains a lot of query functionality and > >>> additional data (e.g. a big list of CRS) - while Geopackage does not > >> > >> That would be a very big list of CRS, or does the query functionality > >> take that much space? I often used spatialite, but given that I > >> normally use it to store many layers, I had actually never noticed the > >> large initial size. This is imho indeed a clear disadvantage when used > >> for data sharing. > >> > >>> When you checked filesizes for shp: did you only look at the shp, or > >>> also include dbf, shx, prj, etc.? Otherwise you comparing a complete > >>> dataset with attributes and metadata against just geometry. > >> > >> All files, not only the *.shp file. I just created a simple vector layer > >> in QGIS and saved it as shapefile, geopackage and spatialite file. > >> > >> > >> Seems I'm a bit confused by the differences between spatialite and > >> sqlite. > >> > >> A spatialite db is always 4 MB + x which makes a huge difference for > >> small layers, but I guess the differences become closer when having > >> "normal" sized layers. > >> > >> What is irritating me is, when I use a small layer and perform some > >> processing function and then save it as .sqlite to a file, the result is > >> only a few kb and not 4 MB. > >> > >> So, having sqlite as default temporary output in processing would not > >> make any difference to ESRI shape sizewise! > >> > >> Example: a shapefile point layer with quite some attributes and 999 > >> features has 4.4 MB > >> saving this as spatialiate: 4.6 MB > >> saving as sqlite: 86 kB ! > >> > >> The sqlite file is 5 times smaller than the ESRI shape file while the > >> spatialite file is about the same as the shape. > >> > >> Here on 2.8.3 at the office I have no geopackage option to test with. > >> > >> So, whats the difference between sqlite and spatialite in detail? > >> > >> Cheers > >> Bernd > >> > >>> Andreas > >>> > >>> On 2015-11-12 15:36, Paulo van Breugel wrote: > >>> > >>> > >>> > >>> On Thu, Nov 12, 2015 at 1:30 PM, Matthias Kuhn <[email protected]> > >>> > >>> wrote: > >>>> The main issues with spatialite are IMO: It's based on sqlite so > >>>> deleting columns and renaming columns is not supported by design. We > >>>> could offer some hacks to bypass this (annoying restriction) from the > >>>> UI - there is a risk of side effects though. Another property of it > >>>> is, that it's already 4-5MB big, even when empty. I consider this a > >>>> major limiting factor as well. Other issues which we were not yet > >>>> able to solve are its management of the information scheme which keep > >>>> duplicate entries of tables and columns which need to be properly > >>>> updated which we apparently do not manage (yet). > >>>> > >>>> Geopackage is also based on sqlite, so the column delete/rename > >>>> restrictions apply as well (with the same workaround possibilities). I > >>>> haven't checked the file size, but if that's smaller, that would be > >>>> quite nice (does somebody know?). > >>> > >>> Just checked saving a shapefile of 941 bytes as Spatialite and > >>> Geopackage file. The first is indeed 4.4MB. The Geopackage is 12.3kB, > >>> i.e., larger then the shapefile, but the increase is small compared to > >>> the spatialite file. I am not familiar with the differences, but this > >>> makes the Geopackage a better candidate imho. > >>> > >>>> All the best > >>>> Matthias > >>> > >>> _______________________________________________ > >>> Qgis-user mailing list > >>> [email protected] > >>> List info: http://lists.osgeo.org/mailman/listinfo/qgis-user > >>> Unsubscribe: http://lists.osgeo.org/mailman/listinfo/qgis-user > >> > >> -- > >> Erstellt mit Operas E-Mail-Modul: http://www.opera.com/mail/ > >> > >> _______________________________________________ > >> Qgis-user mailing list > >> [email protected] > >> List info: http://lists.osgeo.org/mailman/listinfo/qgis-user > >> Unsubscribe: http://lists.osgeo.org/mailman/listinfo/qgis-user > > _______________________________________________ > Qgis-user mailing list > [email protected] > List info: http://lists.osgeo.org/mailman/listinfo/qgis-user > Unsubscribe: http://lists.osgeo.org/mailman/listinfo/qgis-user -- Spatialys - Geospatial professional services http://www.spatialys.com _______________________________________________ Qgis-user mailing list [email protected] List info: http://lists.osgeo.org/mailman/listinfo/qgis-user Unsubscribe: http://lists.osgeo.org/mailman/listinfo/qgis-user
