Linking points and line layers

Question

I have a points layer and a polyline layer.

The points layer is basically bus stops and the line layer is the road network. The bus stops may or may not fall exactly on the road network layer. I want to create a column in the point layer which contains the ID of the nearest link and also the distance from the link's head node or tail node.

That means I need to find the nearest link wrt each node and also measure the distance of the point on the line from the line's head or tail node.

What tool in QGIS will help me get the above things done?

Answer 1

Below, I propose a Field Calculator approach to obtain the distance from the head of the nearest route.

This approach has two requirement:

• Need to install refFunctions plugin which provides geomnearest function.
• Your road network has to have an unique id field (e.g. "id", "fid", "road_name",...)

Start the Field Calculator on your bus_stops point layer and create a new field with:

line_locate_point(geometry := geometry(get_feature('routes', 'fid', geomnearest('routes', 'fid'))), 
                  point := $geometry)

The above expression is based on assumption that your road network polyline layer's layername is routes and it has unique fid field. Please modify them accordingly.

---

[Update]

As to the question, "I want to find the nearest line and also add its ID in the stop feature", please create another field on your point layer by:

geomnearest('routes', 'fid')