Frequently asked questions and answers
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Why does `intersects()` return `False` for a point on a line?
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Determining if a line and a point intersect is complicated by the inherent
inexactness of floating point values. There is no solution for this. Comparing
the distance between a line and point to a tolerance value may be a useful
approach for some applications. Line vs line intersection, on the other hand,
is robust.

See also: https://libgeos.org/usage/faq/#robustness.

I installed shapely in a conda environment using pip. Why doesn't it work?
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Shapely versions < 2.0 load a GEOS shared library using ctypes. It's not
uncommon for users to have multiple copies of GEOS libs on their system.
Loading the correct one is complicated and shapely has a number of
platform-dependent GEOS library loading bugs. The project has particularly poor
support for finding the correct GEOS library for a shapely package installed
from PyPI *into* a conda environment. We recommend that conda users always get
shapely from conda-forge.

Are there references for the algorithms used by shapely?
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Generally speaking, shapely's predicates and operations are derived from
methods of the same name from GEOS_ and the `JTS Topology Suite`_.  See the
`JTS FAQ`_ for references describing the JTS algorithms.

I used .buffer() on a geometry with Z coordinates. Where did the Z coordinates go?
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The buffer algorithm in GEOS_ is purely two-dimensional and discards any Z
coordinates. This is generally the case for the GEOS algorithms.


.. _GEOS: https://libgeos.org/
.. _JTS Topology Suite: https://locationtech.github.io/jts/
.. _JTS FAQ: https://locationtech.github.io/jts/jts-faq.html#E1