GPKGGeometryColumns

The GPKGGeometryColumns table is a mandatory table within a GeoPackage file that defines the geometry columns of feature tables. Each row in this table corresponds to a single geometry column within a GeoPackage. It acts as a catalog for the spatial data stored in the GeoPackage, providing essential metadata about each geometry.

The table contains several key columns. The name column identifies the name of the feature table to which the geometry column belongs. The columnName specifies the name of the actual geometry column within that feature table. The srs_id refers to the Spatial Reference System Identifier associated with the geometries in that column, linking to the GeoPackageSrs table for detailed SRS information. The type column indicates the type of geometry stored, such as point, linestring, polygon, or collections of these. Finally, the is_nullable column specifies whether the geometry column can contain null values. This table is crucial for applications to correctly interpret and access the spatial data within a GeoPackage.