Shapely Polygon creating empty polygon

[MRAB]

On 2022-01-04 22:57, Israel Brewster wrote:
> I’m running into an issue with shapely that is baffling me. Perhaps someone here can help out?
> 
> When running shapely directly from a python 3.8 interpreter, it works as expected:
> 
>>>> import shapely
>>>> shapely.__version__
> '1.8.0'
>>>> from shapely.geometry import Polygon
>>>> bounds = [-164.29635821669632, 54.64251856269729, -163.7631779798799, 54.845450778742546]
>>>> print(Polygon.from_bounds(*bounds))
> POLYGON ((-164.2963582166963 54.64251856269729, -164.2963582166963 54.84545077874255, -163.7631779798799 54.84545077874255, -163.7631779798799 54.64251856269729, -164.2963582166963 54.64251856269729))
> 
> However, if I put this exact same code into my Flask app (currently running under the Flask development environment) as part of handling a request, I get an empty polygon:
> 
>>>>    import shapely
>>>>    print(shapely.__version__)
>>>>    from shapely.geometry import Polygon
>>>>    print(Polygon.from_bounds(*bounds))

In that piece of code you didn't set 'bounds'. It might be worth setting 
it or at least printing it out to double-check.
> 
> Output:
> 
> 1.8.0
> POLYGON EMPTY
> 
> In fact, *any* attempt to create a polygon gives the same result:
>>>> test = Polygon(((1, 1), (2, 1), (2, 2)))
>>>> print(test)
> POLYGON EMPTY
> 
Did you try that piece of code both in Flask and from the command line, 
again to double-check.

> What am I missing here? Why doesn’t it work as part of a Flask request call?
>