AutoGPKGStart Stop

Creating / Destroying of a VirtualGPKG wrapper

--> 'List of Sql-Commands'

<-- 'Index Page for GeoPackage - Commands'

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Original Documentation 'SQL functions implementing OGC GeoPackage compatibility'

• AutoGPKGStart( void ) : Integer
• AutoGPKGStop( void ) : Integer

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• This function will inspect the DB layout, then automatically creating/refreshing a VirtualGPKG wrapper for each GPKG geometry table

  • returns amount of tables effected

• sample 20140101.world_Haiti.gpkg

  • a valid R10 GeoPackage
    • 'CheckGeoPackageMetaData' returns 1
      • 1 features [Geometry] table called geonames
      • 1 tiles [Raster] table called fromosm_tiles

SELECT AutoGPKGStart();

• returns 1
  • 1 features [Geometry] table found
  • a new table called vgpkg_geonames now exists
    • the show CREATE statement shows:
      • CREATE VIRTUAL TABLE "vgpkg_geonames" USING VirtualGPKG("geonames")

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• when viewing the Geometry field with BLOB explore
  • geonames: shows BLOB sz=?? UNKNOWN type
    • a Geometry in the gpkg-format
  • vgpkg_geonames: shows BLOB sz=?? GEOMETRY
    • a Geometry in the spatialite-format
      • 'GeomFromGPB'
        • will not be needed to retrieve these Geometries

Note: at this point there is no (Spatialite-specific) SpatialIndex

• 'CreateSpatialIndex'
  • will fail in a GeoPackage
    • due to the missing, spatialite-specific, geometry_columns TABLE

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2014-05-23: Mark Johnson, Berlin Germany

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