Snap lines to points automatically?

Question

I have two vector shapefiles: One file is points representing manholes and the other is a polyline file representing pipes leading to and from the manholes. I need to snap the lines within a specified distance to the closest manhole.

Is there an easy way to accomplish this without doing it manually?

Update

As per Alexandre, I have exported my shapefiles to spatialite format. Not sure what to next.

Update #2 I created a new db file and imported shapefiles into the new db using spatialite-gui, I adjusted my SQL query but as you can see I get an error "no such column: f.geom"

Answer 1

If you are willing to put your data in Postgis (or Spatialite), you could use ST_Snap to do what you want.

Just use lines layer\table as input, and your points layer as reference, and set the tolerance. Something like this:

SELECT
    f.gid as gid,
    ST_Snap(f.Geometry, g.Geometry, 2) as geom
FROM
    pipe as f,
    (SELECT ST_Collect(Geometry) as Geometry
     FROM mh) as g

The result is this:

You can then update your geometries using the feature identifier.

Answer 2

I don't know much about QGIS or GRASS, but some quick Googling has yielded v.clean in GRASS should do the trick.

Have a look at this post and this one.

Alternatives to QGIS and GRASS:

If I were to do this in ArcGIS, I would probably store my data in a Feature Dataset in a File Geodatabase and create a Topology to identify areas where the point layer was not on the endpoints of the lines. You can then fix the errors using the Error Inspector.

But, probably the quickest and easiest solution would be in FME. You could try using the Snapper Tool or better yet, the AnchoredSnapper Tool. If you use the AnchoredSnapper, make sure your snapping type is End Point Snapping. Of course, you will need a license for FME. But you can download a 14 day trial if you don't have one.

Answer 3

In QGIS Snap Geometries to layer will do what you want. See this thread How to snap lines to nearest point?

Answer 4

Manual way

Qgis -> Settings -> Snapping options (and I'm not sure but it might need CadTools extension) and enable topological editing.

Automatic way

v.clean which is in GRASS tools in SEXTANTE toolbox in QGIS. If you have PostGIS 2.0 then ST_Snap and ST_SnapToGrid() (And there is no reason why you cant use it, it's very good spatial tool)

Commercial way

FME and MRF tool (commercial extension, I had an evalution version. It vas very good).

Also I'm intrested about water pipe/sewer management with open source tools, do you have any hints?