filters.attribute

The attribute filter allows you to set the values of a selected dimension. Two scenarios are supported:

  • Set the value of a dimension of all points to single value (use option ‘value’)
  • Set points inside an OGR-readable Polygon or MultiPolygon (use option ‘datasource’)

OGR SQL support

You can limit your queries based on OGR’s SQL support. If the filter has both a datasource and a query option, those will be used instead of the entire OGR data source. At this time it is not possible to further filter the OGR query based on a geometry but that may be added in the future.

Note

The OGR SQL support follows the rules specified in ExecuteSQL documentation, and it will pass SQL down to the underlying datasource if it can do so.

Example 1

In this scenario, we are altering the attributes of the dimension ‘Classification’. Points from autzen-dd.las that lie within a feature will have their classification to match the ‘CLS’ field associated with that feature.

{
  "pipeline":[
    "autzen-dd.las",
    {
      "type":"filters.attribute",
      "dimension":"Classification",
      "datasource":"attributes.shp",
      "layer":"attributes",
      "column":"CLS"
    },
    {
      "filename":"attributed.las",
      "scale_x":0.0000001,
      "scale_y":0.0000001
    }
  ]
}

Example 2

This pipeline sets the PointSourceId of all points from ‘autzen-dd.las’ to the value ‘26’.

{
  "pipeline":[
    "autzen-dd.las",
    {
      "type":"filters.attribute",
      "dimension":"PointSourceId",
      "value":26
    },
    {
      "filename":"attributed.las",
      "scale_x":0.0000001,
      "scale_y":0.0000001
    }
  ]
}

Example 3

This example sets the Intensity attribute to CLS values read from the OGR SQL query.

{
  "pipeline":[
    "autzen-dd.las",
    {
      "type":"filters.attribute",
      "dimension":"Intensity",
      "datasource":"attributes.shp",
      "query":"SELECT CLS FROM attributes where cls!=6",
      "column":"CLS"
    },
    {
      "filename":"attributed.las",
    }
  ]
}

Options

dimension
Name of the dimension whose value should be altered. [Default: none]
value
Value to apply to the dimension. [Default: none]
datasource
OGR-readable datasource for Polygon or MultiPolygon data. [Default: none]
column
The OGR datasource column from which to read the attribute. [Default: first column]
query
OGR SQL query to execute on the datasource to fetch geometry and attributes. [Default: none]
layer
The data source’s layer to use. [Defalt: first layer]