filters.overlay

filters.overlay#

The overlay filter allows you to set the values of a selected dimension based on an OGR-readable polygon or multi-polygon.

Default Embedded Stage

This stage is enabled by default

Streamable Stage

This stage supports streaming operations

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.

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

Example 2#

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

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

Options#

bounds: A bounds to pre-filter the OGR datasource that is passed to OGR_L_SetSpatialFilter in the form ([xmin, xmax], [ymin, ymax]).
dimension: Name of the dimension whose value should be altered. [Required]
datasource: OGR-readable datasource for Polygon or MultiPolygon data. [Required]
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. The entire layer is fetched if no query is provided. [Default: none]
layer: The data source’s layer to use. [Default: first layer]
threads: The number of threads to use. Only valid in standard mode. [Default: 1]

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]