[GRASS-user] Defect v.edit tool=break with multiple coordinates

[Johannes Radinger]

Hi all,

I presumably detected an problem/bug with v.edit and its tool "break". I
wanted to break a line at multiple coordinates. But the result is an
overlay of multiple lines instead of the original line that is broken into
segments. Here a small reproducible example using the NC dataset:

from grass.script import core as grass

# Copy data from PERMANENT mapset
grass.run_command("g.copy",
    overwrite=True,
    vector="railroads at PERMANENT,railroads")
grass.run_command("v.extract",
    overwrite=True,
    input="firestations at PERMANENT",
    cat="58,66,29,35,31,32",
    output="firestations")

# Connectors to find exact break points coords
grass.run_command("v.distance",
    overwrite=True,
    to="railroads",
    from_="firestations",
    output="firestations_connectors")
firestations_connectors_coors = grass.read_command("v.to.db",
    flags="p",
    map="firestations_connectors",
    option="end",
    separator="comma").splitlines()
firestations_connectors_coors = [[",".join(x.split(",")[1:3])] for x
in firestations_connectors_coors[1:]]

# Break at point coords
grass.run_command("v.edit",
      tool="break",
      map="railroads",
      coords=firestations_connectors_coors,
      threshold=50,
      layer=1,
      cats="1-99999999")


My system:
GRASS version: 7.4.1

GRASS SVN revision: r72807M

Build date: 2018-06-13

Build platform: x86_64-apple-darwin17.6.0

GDAL: 2.0.0

PROJ.4: 5.1.0

GEOS: 3.6.2

SQLite: 3.19.3

Python: 2.7.15

wxPython: 4.0.0

Platform: Darwin-17.7.0-x86_64-i386-64bit

I seems that this issue has already been detected long time ago (see
https://trac.osgeo.org/grass/ticket/2903). I extended the bug ticket with
my experience and details using the new GRASS versions. Interestingly, all
people that reported about this problem were working on MacOS?!

Can anybody else reproduce this problem? Or does someone know a solution?

Cheers,
Johannes
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