filters.iqr

The filters.iqr filter automatically crops the input point cloud based on the distribution of points in the specified dimension. Specifically, we choose the method of Interquartile Range (IQR). The IQR is defined as the range between the first and third quartile (25th and 75th percentile). Upper and lower bounds are determined by adding 1.5 times the IQR to the third quartile or subtracting 1.5 times the IQR from the first quartile. The multiplier, which defaults to 1.5, can be adjusted by the user.

Note

This method can remove real data, especially ridges and valleys in rugged terrain, or tall features such as towers and rooftops in flat terrain. While the number of deviations can be adjusted to account for such content-specific considerations, it must be used with care.

Default Embedded Stage

This stage is enabled by default

Example

The sample pipeline below uses filters.iqr to automatically crop the Z dimension and remove possible outliers. The multiplier to determine high/low thresholds has been adjusted to be less agressive and to only crop those outliers that are greater than the third quartile plus 3 times the IQR or are less than the first quartile minus 3 times the IQR.

{
  "pipeline":[
    "input.las",
    {
      "type":"filters.iqr",
      "dimension":"Z",
      "k":3.0
    },
    "output.laz"
  ]
}

Options

k
The IQR multiplier used to determine upper/lower bounds. [Default: 1.5]
dimension
The name of the dimension to filter.