vapour_geom_name function

Read geometry column name

Read geometry column name

There might be one or more geometry column names, or it might be an empty string.

vapour_geom_name(dsource, layer = 0L, sql = "")

Arguments

  • dsource: data source name (path to file, connection string, URL)
  • layer: integer of layer to work with, defaults to the first (0) or the name of the layer
  • sql: if not empty this is executed against the data source (layer will be ignored)

Returns

character vector of geometry column name/s

Details

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.

Examples

file <- system.file("extdata/tab/list_locality_postcode_meander_valley.tab", package = "vapour") vapour_geom_name(file) ## empty string