Hi! A question related to this. I have set up a PostGIS structure with tables, rules, views, triggers and constraints. To this there is a QGIS project with styling, forms, relations and so on. If I want to make a file based version of this for testing, working copies, versions, distribution etc. where do I put the database logic? Could it fit in a file based database or virtual layers? Which strategy is the best? Any ideas or experiences?
Regards Karl-Magnus Jönsson Från: Qgis-user [mailto:qgis-user-boun...@lists.osgeo.org] För Bo Victor Thomsen Skickat: den 13 september 2018 22:40 Till: qgis-user@lists.osgeo.org Ämne: Re: [Qgis-user] Geopagkage and "geom" in DBmanager Ok, after some googling, I have a glimmer of understanding of the (technical and personal) issues. Enough said about that... So technically, GPKG support in QGIS is a hybrid of a "simple" GPKG implementation bundled/merged with the spatialite sqlite-extension incl. conversion functions, so you can convert the GPKG binary object to and fro a spatialite ditto - when you have to use som spatialite-specific functionality like spatial SQL, projection support and so on ? (If there is a web page somewhere that explains this in detail, i'll respecfully redraw my questions and do some RTFM) Regards Bo Victor Thomsen Den tor. 13. sep. 2018 kl. 16.00 skrev Luigi Pirelli <lui...@gmail.com<mailto:lui...@gmail.com>>: you should look into the history of the gpkg format definition vs spatialite format adoption. Nothing related with QGIS, or gdal or etc etc Luigi Pirelli ************************************************************************************************** * LinkedIn: https://www.linkedin.com/in/luigipirelli * Stackexchange: http://gis.stackexchange.com/users/19667/luigi-pirelli * GitHub: https://github.com/luipir * Mastering QGIS 2nd Edition: * https://www.packtpub.com/big-data-and-business-intelligence/mastering-qgis-second-edition * Hire me: http://goo.gl/BYRQKg ************************************************************************************************** On Thu, 13 Sep 2018 at 14:30, Bo Victor Thomsen <bo.victor.thom...@gmail.com<mailto:bo.victor.thom...@gmail.com>> wrote: Ok.. From the Spatialite 4.2.0 wiki: · CastAutomagic(): will indifferently accept both GPKG and SpatiaLite BLOB Geometries, then returning anyway a SpatiaLite's own BLOB Geometry. I can confirm, that using the "CastAutomagic(geom)" function instead of the simple field "geom" will get the st_area and other ogc functions in the QGIS Databasemanager Dataprovider for GeoPackage to work. That means that the geopackage binary format for geometry is incompatible with the underlying spatialite spatial system and functions. This is not the most helpful and thoughtful user oriented solution I've encountered ... Or should I have RTFM somewhere in the QGIS.org site ? However it does work. Thanks for the tip Den tor. 13. sep. 2018 kl. 13.20 skrev Jean-Baptiste Desbas <jb.des...@gmail.com<mailto:jb.des...@gmail.com>>: Hi, I have to use st_area(CastAutomagic(geom)) instead of st_area(geom), otherwise null column is retourned. Le jeu. 13 sept. 2018 à 11:45, Bo Victor Thomsen <bo.victor.thom...@gmail.com<mailto:bo.victor.thom...@gmail.com>> a écrit : Hi Lene - I've made a few observations regarding the use of GeoPackage in DBManager... I have a GeoPackage based table called "renhold" containing polygons. Primary key column is an integer called "fid" and the geometry column is called "geom" - It's pretty close to your setup If I use the DBManager with the GeoPackage dataprovider and execute the following statement: select fid, st_area (geom) from renhold , it returns a table with 2 columns as expected. However , column nr. 2 contains only nulls. However, the statement does not result in an error. The function "st_area" simply doesn't return a value besides null. An now the mystery!! : If I use the DBManager with the Virtual Layers -> Project layers dataprovider and execute the following statement: select fid, st_area (geometry) from renhold , it returns a table with 2 columns as expected. And column nr. 2 do contain the expected area values. Go figure... NB! The "renhold" layer is visible in the map and named "renhold" NBB! In the Virtual Layers dataprovider you have to use the standard name "geometry" to represent the geometry column - not the real column name ("geom" in this case) Actually I have a reasonable explanation: The 2 different dataproviders uses different internal functions to calculate the area. However the function used by the GeoPackage Dataprovider doesn't work ! Regards Bo Victor Thomsen LIFA Denamrk Den tor. 13. sep. 2018 kl. 09.27 skrev Alexandre Neto <senhor.n...@gmail.com<mailto:senhor.n...@gmail.com>>: Hi Lee, Can you try removing the quotation marks around geom? Best wishes, Alex Neto A qui, 13/09/2018, 02:04, Lene Fischer <l...@ign.ku.dk<mailto:l...@ign.ku.dk>> escreveu: Hi, Trying out a geopackage layer in DBManager asking a simple SQL statement st_area But when I try to write a statement like this SELECT "vandopland".* , st_area("vandopland"."geom") as areal_m2 FROM "vandopland" "geom" is not found. Suggestions as geomfromexifgpsblob or geomfromfgf or geomfromwkb . Then I get "an error occured" Any suggestions what I might have done wrong. Regards from a newbee Geopagkace/DBmanager Lene Fischer _______________________________________________ Qgis-user mailing list Qgis-user@lists.osgeo.org<mailto:Qgis-user@lists.osgeo.org> List info: https://lists.osgeo.org/mailman/listinfo/qgis-user Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user -- Alexandre Neto --------------------- @AlexNetoGeo http://sigsemgrilhetas.wordpress.com http://gisunchained.wordpress.com _______________________________________________ Qgis-user mailing list Qgis-user@lists.osgeo.org<mailto:Qgis-user@lists.osgeo.org> List info: https://lists.osgeo.org/mailman/listinfo/qgis-user Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user -- Med venlig hilsen Bo Victor Thomsen _______________________________________________ Qgis-user mailing list Qgis-user@lists.osgeo.org<mailto:Qgis-user@lists.osgeo.org> List info: https://lists.osgeo.org/mailman/listinfo/qgis-user Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user -- Med venlig hilsen Bo Victor Thomsen _______________________________________________ Qgis-user mailing list Qgis-user@lists.osgeo.org<mailto:Qgis-user@lists.osgeo.org> List info: https://lists.osgeo.org/mailman/listinfo/qgis-user Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user -- Med venlig hilsen Bo Victor Thomsen
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