We currently have mixed behaviour on the handling of missing indices in the geometry creation functions.

I'd like to decide on this and make it consistent. This already arised in #322.

Do we want this?

>>> pygeos.linestrings([[0.1, 0.1], [0.2, 0.2]], indices=[1, 1])
[None, Geometry("LINESTRING (0.1 0.1, 0.2 0.2)")]

Or this?

pygeos.multipoints([pygeos.Geometry("POINT (1 1)")] * 2, indices=[1, 1])
>>> array([<pygeos.Geometry MULTIPOINT EMPTY>,
                 <pygeos.Geometry MULTIPOINT (1 1, 1 1)>], dtype=object)

We basically have 3 options:

• raise an exception (like what is done when you supply 1 coordinate for a linestring)
• insert an EMPTY geometry (but; LINEARRING EMPTY does not exist, so what to do there?)
• insert a None

I am tending towards the first option. It is always better to make it more strict, then you can keep backwards compatibility when changing it later. What do you think @jorisvandenbossche @brendan-ward ?