There might be one or more geometry column names, or it might be an empty string.
vapour_geom_name(dsource, layer = 0L, sql = "")data source name (path to file, connection string, URL)
integer of layer to work with, defaults to the first (0) or the name of the layer
if not empty this is executed against the data source (layer will be ignored)
character vector of geometry column name/s
It might be "", or "geom", or "ogr_geometry" - the last is a default name given when SQL is executed by GDAL but there was no geometry name, and 'SELECT * ' or equivalent was used.
This feature is required by the DBI backend work in RGDALSQL, so that when SELECT * is used
we can give a reasonable name to the geometry column which is obtained separately.
file <- system.file("extdata/tab/list_locality_postcode_meander_valley.tab", package = "vapour")
vapour_geom_name(file) ## empty string
#> [1] ""