#2798: v.centerline fails with real data
--------------------------+-------------------------
Reporter: martinl | Owner: grass-dev@…
Type: defect | Status: new
Priority: normal | Milestone:
Component: Addons | Version: svn-trunk
Keywords: v.centerline | CPU: Unspecified
Platform: Unspecified |
--------------------------+-------------------------
I tried `v.centerline` to produce center line for highways in CZ imported
from OSM, see attachment:highway.pack.
{{{
v.centerline input=highway out=highway_c
}}}
The result is one small line (red color) located somewhere in the space,
see attachment:v-center-line.png.
I tried `v.centerline` to produce center line for highways in CZ imported
from OSM, see (1), EPSG:5514 (you can use also 2065 if you have Proj.4
<4.9).
{{{
v.centerline input=highway out=highway_c
}}}
The result is one small line (red color) located somewhere in the space,
see attachment:v-center-line.png.
#2798: v.centerline fails with real data
--------------------------+--------------------------
Reporter: martinl | Owner: grass-dev@…
Type: defect | Status: new
Priority: normal | Milestone: 7.0.1
Component: Addons | Version: svn-trunk
Resolution: | Keywords: v.centerline
CPU: Unspecified | Platform: Unspecified
--------------------------+--------------------------
Comment (by mlennert):
v.centerline is meant for bundles of lines that have more of less the same
trajectory and for which you want to define one "mean" line. As shown in
the examples in the man page this could be two lines representing the
riverbanks, or more lines representing the variance of trajectories along
a more or less similar direction, such as lines of flight of airplanes
above a specific area.
I don't really know what the "centerline" should be in your case ?
I added a few words to the man page to hopefully make this more explicit.
If you think the module should do something else, than please go ahead and
modify it. I'm leaving the ticket open for now, but at this stage, this is
a "wontfix" or even a "worksforme" in my eyes.
#2798: v.centerline fails with real data
--------------------------+--------------------------
Reporter: martinl | Owner: grass-dev@…
Type: defect | Status: new
Priority: normal | Milestone: 7.0.1
Component: Addons | Version: svn-trunk
Resolution: | Keywords: v.centerline
CPU: Unspecified | Platform: Unspecified
--------------------------+--------------------------
Comment (by martinl):
Replying to [comment:4 mlennert]:
> v.centerline is meant for bundles of lines that have more of less the
same trajectory and for which you want to define one "mean" line. As shown
in the examples in the man page this could be two lines representing the
riverbanks, or more lines representing the variance of trajectories along
a more or less similar direction, such as lines of flight of airplanes
above a specific area.
it seems to me that this also that case, there are two traffic lines for
each highway.
> I don't really know what the "centerline" should be in your case ?
#2798: v.centerline fails with real data
--------------------------+--------------------------
Reporter: martinl | Owner: grass-dev@…
Type: defect | Status: new
Priority: normal | Milestone: 7.0.1
Component: Addons | Version: svn-trunk
Resolution: | Keywords: v.centerline
CPU: Unspecified | Platform: Unspecified
--------------------------+--------------------------
Comment (by mlennert):
Replying to [comment:5 martinl]:
> Replying to [comment:4 mlennert]:
> > v.centerline is meant for bundles of lines that have more of less the
same trajectory and for which you want to define one "mean" line. As shown
in the examples in the man page this could be two lines representing the
riverbanks, or more lines representing the variance of trajectories along
a more or less similar direction, such as lines of flight of airplanes
above a specific area.
>
> it seems to me that this also that case, there are two traffic lines for
each highway.
>
> > I don't really know what the "centerline" should be in your case ?
>
> A line between two traffic lines.
After importing and zooming I can see what you mean. In order to get the
centerlines of each of the highway pieces, you would have to iterate
through them and apply v.centerline to each of them as v.centerline in its
current state takes all lines in the map at once.