Creating line connecting point to two nearest points of other layer with overlay_nearest function using QGIS Expression

Question

In QGIS 3.22 I have two point layers named:

• 'source_p'
• 'target_p'

I want to point automatically with a line from the 'source_p' layer to the two nearest points on the 'target_p' layer.

Manually, I was able to generate such code where the 'target_p' layer refers to the "parent" field in the 'source_p' layer.

make_line( 
  $geometry ,  
  geometry( 
    get_feature('target_p', 'fid', parent)
  )
)

Answer 1

Use the following expression with the following functions:

1. array_foreach() (to create two lines) and
2. collect_geometries() to convert the array of lines to actual lines (geometries)

collect_geometries (
    array_foreach (
        overlay_nearest (
            'target_p',  -- rename the layer if necessary
            $geometry,
            limit:=2
        ),
        make_line (
            $geometry,
            @element
        )
    )
)

The expression used on the source_p layer (red points) to create lines to the two nearest points from targe_p layer (blue dots):