[Qgis-user] topology checker - Check if point features are covered by line features

[Nicolas Cadieux]

Hi,

I don’t have QGIS in front of me.  I looked around on the the net and was surprised to see the «covered By » option for points and lines.  Unless a line is snapped, or intersects a point exactly on a Line node, it’s just about impossible to calculate if a line « covers » a point.  This is something easy to do with a polygon but not a line because of float point precision error.  You could buffer the lines and see if that helps. You could create a 1m buffer on the line (or the point).  Make sure both layers are in the same crs so that additional calculations don’t need to be done. 

You could at the « select by location » side.  I would look at « snap with » or «intersects with »options.

Nicolas Cadieux
Ça va bien aller!

> Le 13 avr. 2020 à 06:11, Marshal Mappers <marshalmappers at gmail.com> a écrit :
> 
> 
> Hello everyone,
> I want to use the topology checker to check if point features are covered by line features. For example are the bus stops covered by the bus lines.
> Therefore I use the topology checker with the following rule: "points" must be covered by "lines". But I get the error for all points that "point is not covered by segment". 
> I even get the error for points that I edited on the line with snapping.
> Here my questions:
> 1. Is it possible to check if point features are covered by line features? With topology checker? In general?
> 2. What does the rule: "points" must be covered by "lines"check? Under what cicumstances is a point feature covered by a line feature?
> 
> I tried this in QGIS Versions 2.18.26; 3.4.15; 3.10.2
> My OS ist Windows 10
> I tried with shapefiles and geopackage layers
> The CBS of point and line layers are the same. Here I tried the coordinate systems with epgs: 31468 (DHDN / 3---degree Gauss-Kruger zone 4) and 25832 (ETRS89 / UTM zone 32N).
> If anyone could explain or point me to the right direction, that would be awesome.
> 
> Thank you!
> 
> Best regards 
> 
> Marshal
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