.. _filters.radialdensity:

===============================================================================
filters.radialdensity
===============================================================================

The **Radial Density filter** creates a new attribute ``RadialDensity`` that
contains the density of points in a sphere of given radius.

The density at each point is computed by counting the number of points falling
within a sphere of given radius_ (default is 1.0) and centered at the current
point. The number of neighbors (including the query point) is then normalized
by the volume of the sphere, defined as

.. math::

  V = \frac{4}{3} \pi r^3

The radius :math:`r` can be adjusted by changing the radius_ option.

.. embed::

Example
-------------------------------------------------------------------------------

.. code-block:: json

  [
      "input.las",
      {
          "type":"filters.radialdensity",
          "radius":2.0
      },
      {
          "type":"writers.bpf",
          "filename":"output.bpf",
          "output_dims":"X,Y,Z,RadialDensity"
      }
  ]


Options
-------------------------------------------------------------------------------

_`radius`
  Radius. [Default: 1.0]

