QGIS Cross Tab of Towns and Routes

Question

Using QGIS, I have a layer with 100 towns. I have another layer with 200 cycle routes, each with a different name. I want to create (automatically natch) a table that will help the people in each town, for example, get a list of all of the routes that pass within 1Km of their town centre.

Answer 1

If you bring your layers into Spatialite, here's a one-liner to get what you want:

SELECT t.id, b.Trail_Name FROM towns AS t, bike_trails AS b
WHERE ST_Intersects(b.Geometry, BUFFER(t.Geometry, 1000));

This query will select each bike_trail name from the bike_trails layer which passes within 1000 m of a town, and list all the town ID's with each trail name.