[gdal-dev] How to recognize FDO style SQLite db?

[Jukka Rahkonen]

Hi,

User in gis.stackoverflow tried to use SQL "select ST_Union(geometry)" for
the Natural Earth SQLite db file from
http://naciscdn.org/naturalearth/packages/natural_earth_vector.sqlite.zip.

The query yields an empty geometry because the NE database is written with
FDO geometries instead of SpatiaLite geometries. What I wonder is that does
GDAL user have any simple mean for getting informed if SQLite db is FDO or
Spatialite. If SpatiaLite is present a clever enough user can use ogrinfo
and check from
https://www.gaia-gis.it/gaia-sins/spatialite-sql-latest.html#p16fdo that
value 2 is returned in case when "both tables exist, and their layout is the
one used by FDO/OGR"

ogrinfo -sql "select CheckSpatialMetaData()"  
natural_earth_vector.sqlite
INFO: Open of `natural_earth_vector.sqlite'
      using driver `SQLite' successful.

Layer name: SELECT
Geometry: None
Feature Count: 1
Layer SRS WKT:
(unknown)
CheckSpatialMetaData(): Integer (0.0)
OGRFeature(SELECT):0
  CheckSpatialMetaData() (Integer) = 2


However, the one who knows to do that must be somewhat advanced GDAL and
Spatialite user.

-Jukka Rahkonen-