qgisqgis-processing
I have large number of points(As a point layer) and few line(Roads basically), how do I remove points which are not falling on line layer.
I tried several methods like-
Some how QGIS gets crashed while running algorithm.
I am using QGIS 2.18.14 and QGIS 2.18.14
You can use Join by location to join polyline with point shapefiles. However, the point should be exactly snapped to the line in order to be joined, otherwise, it is better to create a buffer of polygon shapefile around the road lines of distance that you can decide after several tests, then use the buffered polygon to join the points by location. To find the tool, you can go to Vector -> Data management tools -> Join by location, as you can see below:
The output polygon will create a count field in the attribute table of the number of accident points:
I used QGIS 2.14.8 for the above process.
VirtualLayers possibly to the first world problem rescue; this is a nice solution if you can express your polygon selection with some condition (I use an id <some_id> as an example here):
and then type
SELECT pts.*
FROM <point_layer> AS pts,
<polygon_layer> AS plg
WHERE plg.<id_column> = <some_id>
AND ST_Intersects(pts.geometry, plg.geometry);
into the Query field.
If you want to manually select features:
and continue with your usual workflow from there
(you could of course use that layer in the above query to get the intersecting points into a virtual layer; just omit plg.<id_column> = <some_id> AND in above query and replace <polygon_layer> with the name of the scratch layer).
Best Answer
The possibility that a certain point falls onto a certain line is unlikely. I recommend to calculate a buffer around your line (for example: 10m) and compute the intersection with the already given tool
Vector > Geoprocessing Tool > Intersectionwhich should be left over just the "intersecting" points.The distance threshold for the boundary is up to you but depends on your data quality and requirements