Hi,
Small correction,
If you extract the end nodes (vertices) of the line, you can use the
following rule. End node layer must be covered by endpoints of line
layer or node layer must be covered by line. I therefore assume the
QGIS topology checker can work for endnode only and not for "middle
node" of the line. This is should be reported as a bug I think.
Nicolas
On 2020-04-17 12:42 p.m., Nicolas Cadieux wrote:
Hi Marshal,
I looked at your data. The first problem is that none or your line
nodes intersect with a point. It looks close... but it's not close
enough. By using "snap geometry location", I was able to create a new
line that snaps to your point. (called Topologie snapped_line in the
file I will send you in private). A "Select by location" or a "Join
Attributes by location" confirms that the points now intersect the
Topologie snapped line layer. The Join Attributes by location will
permit you to find the problems as you can discard records that do not
intersect. This will give you what you want.
As for the topology Checker, it seems that a line cannot cover a point
or a point cannot cover a line even if point and line nodes intersect
(Can someone confirm this?). I can only assume that QGIS works with
the correct assumption that a point and a line does not have a surface
to cover and therefore, cannot cover anything. I assume, based on
your observations that ESRI does not follow that assumption.
You can however create a 1 m buffer around your line (Topologie
Buffered_line in the file). Then, you can create the rule (polygon
must contain point). That rule will work in the topology Checker.
Cheers!
Nicolas
On 2020-04-13 10:25 a.m., Nicolas Cadieux wrote:
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 <[email protected]>
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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