1

In the Shapely package, there is a function that allows you to determine whether coordinates include a Z value. It is object.has_z.

Is there a way that a similar command can be carried on the geometry column of a SQLite table?

2

If you have a SpatiaLite database you can use the SQL function ST_Is3D http://www.gaia-gis.it/gaia-sins/spatialite-sql-latest.html. Example that returns "1" as a result

SELECT ST_Is3d(ST_GeomFromText('POINTZ (1 1 1)'));

CoordDimension and ST_NDims can by used as well, the first returns "XYZ" and the latter "3" but I think that ST_Is3D is the best match for you.

  • I tried that but I get "-1" as a results, which the link says is "for UNKNOWN corresponding to a function invocation on invalid arguments." I am calling it with this code conn.execute("SELECT ST_Is3d(ST_GeomFromText('a_table'));"). Is that correct? – Perfalcon Jun 4 '19 at 13:24
  • 1
    No, that's not correct SQL. If your table is named "my_table" and the geometry field is "geom" do SELECT ST_Is3D(geom) FROM my_table. – user30184 Jun 4 '19 at 13:28

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