filters.griddecimation

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filters.griddecimation#

The grid decimation filter transform only one point in each cells of a grid calculated from the points cloud and a resolution therm. The transformation is done by the value information. The selected point could be the highest or the lowest point on the cell. It can be used, for exemple, to quickly filter vegetation points in order to keep only the canopy points.

Default Embedded Stage

This stage is enabled by default

Example#

This example transform highest points of classification 5 in classification 9, on a grid of 0.75m square.

[
   "file-input.las",
  {
      "type": "filters.gridDecimation",
      "output_type":"max",
      "resolution": "0.75",
      "where":"Classification==5",
      "value":"Classification=9"
  },
  {
        "type":"writers.las",
        "filename":"file-output.las"
  }
]

Options#

output_type

The type of points transform by the value information. The value should be "max" for transform the highest point, or "min" for the lowest. [Default: false]

resolution

The resolution of the cells in meter. [Default: 1.]

value

A list of assignment expressions to be applied to points. The list of values is evaluated in order. [Default: none]

where

An expression that limits points passed to a filter. Points that don’t pass the expression skip the stage but are available to subsequent stages in a pipeline. [Default: no filtering]

where_merge

A strategy for merging points skipped by a where option when running in standard mode. If true, the skipped points are added to the first point view returned by the skipped filter. If false, skipped points are placed in their own point view. If auto, skipped points are merged into the returned point view provided that only one point view is returned and it has the same point count as it did when the filter was run. [Default: auto]

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