Graph Coverage Zones from Points
================================

Coverage zones represent areas that can be reached from multiple source points
within a certain **time** or **distance** limit using a transport network.
They are built by calculating reachability per point, generating **Voronoi polygons**,
and optionally clipping them to a defined boundary.

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    The library supports several methods for generating coverage zones,
    depending on whether you use a full transport graph or simplified geometric rules.

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Coverage Using Transport Graph
------------------------------

Uses a full **routing engine** to determine reachable areas per point,
then builds coverage zones based on actual network paths.

.. autofunction:: objectnat.get_graph_coverage

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.. figure:: https://raw.githubusercontent.com/DDonnyy/ObjectNat/assets/coverage_zones_time_10min.png
   :alt: coverage_zones_time_10min
   :align: center
   :width: 80%

   Coverage zones generated by **travel time (10 minutes)** on a transport graph.

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.. figure:: https://raw.githubusercontent.com/DDonnyy/ObjectNat/assets/coverage_zones_distance_600m.png
   :alt: coverage_zones_distance_600m
   :align: center
   :width: 80%

   Coverage zones generated by **distance (600 meters)** on a transport graph.

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Coverage Using Radius Only
--------------------------

Generates fixed **radius-based buffers** per point without routing,
then merges or clips them via **Voronoi** diagrams for cleaner borders.

.. autofunction:: objectnat.get_radius_coverage

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.. figure:: https://raw.githubusercontent.com/DDonnyy/ObjectNat/assets/coverage_zones_radius_distance_800m.png
   :alt: coverage_zones_distance_radius_voronoi
   :align: center
   :width: 80%

   Radius-based coverage zones (800 meters) with Voronoi clipping.

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Stepped Graph Coverage
----------------------

Creates **multi-step coverage zones** (e.g., 5, 10, 15 minutes)
using the full transport graph for each source point.

.. autofunction:: objectnat.get_stepped_graph_coverage

.. figure:: https://raw.githubusercontent.com/DDonnyy/ObjectNat/assets/stepped_coverage_zones_separate.png
   :alt: stepped_coverage_zones_separate
   :align: center
   :width: 80%

   Stepped coverage zones displayed as **separate intervals**.

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.. figure:: https://raw.githubusercontent.com/DDonnyy/ObjectNat/assets/stepped_coverage_zones_voronoi.png
   :alt: stepped_coverage_zones_voronoi
   :align: center
   :width: 80%

   Stepped coverage zones merged using **Voronoi partitioning**.

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.. note::

   Coverage zones are a powerful tool for evaluating **service accessibility**,
   **network efficiency**, and **urban reachability**.

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Example notebook
----------------

:doc:`examples/coverage`