is_simple - empty geometry logic

[anonymous]

The logic around dealing with empty datasets and is_simple seems a little confusing:

An empty line - seg fault (see ​https://svn.boost.org/trac/boost/ticket/11709) An empty multi line - returns false An empty polygon - returns true An empty multi polygon - returns false

Should a multi polygon or linestring that is empty be considered simple. I would think it would as it would not have any anomalous geometric points, such as self intersection or self tangency.

[flippmoke@…]

This also affects multipoints that are empty which are also returned as false.

[mkaravel]

The ticket has been solved as part of GitHub PR 334: ​https://github.com/boostorg/geometry/pull/334

Details:

Empty lines and empty polygons as considered as invalid geometries. As such the result of is_simple is irrelevant. In the current fix (see PR above) is_simple returns false for both these geometries.

On the contrary empty multi-geometries are considered as valid (in reality representing the empty geometry), and with this bug fix they are considered as simple as well.