Shortest distance of point feature from one line in QGIS

Question

I would like to ask for your help with calculating in simple way distance of points feature to one line (for example, what is distance of cities from the national border).

I see there were few topics on this question but I did not manage to calculate it. I tried to use Distance to nearest hub (line to hub) but distances seem to go in the direction of center and not in the direction of the nearest distance.

Answer 1

You may want to select your line using a different criterion, here I opt for the nearest.

To get the shortest distance between points and the (nearest) line feature, you can use the field calculator with this expression:

distance(
    $geometry,            -- the current point geometry
    overlay_nearest(
        'border',         -- the name of your line layer
        $geometry
    )[0]                  -- get the first feature from the array of nearest features
)

To get the distance to the nearest point on the boundary of a polygon:

distance(
    $geometry,
    boundary(                  -- get the boundary of the polygon as a line geometry
        overlay_nearest(       
            'polygon',
            $geometry          
        )[0]                   -- get the polygon nearest to the point
    ) 
)

Note: lines and labels were created separately to visualise the result of the expressions

Get a specific feature using an attribute value:

distance(
    $geometry,
    boundary(
        geometry(
            get_feature(
                'countries',          -- layer name
                'NAME',               -- field name
                'Zambia'              -- attribute value
            )
        )
    )
) / 1000                              -- convert m to km