[GRASS-dev] [GRASS GIS] #719: v.edit tool=break: breaking more then 6 coords and producing of an unexpected line

#719: v.edit tool=break: breaking more then 6 coords and producing of an
unexpected line
--------------------------+-------------------------------
  Reporter: achim | Owner: martinl
      Type: defect | Status: reopened
  Priority: major | Milestone: 7.0.3
Component: Vector | Version: 7.0.2
Resolution: | Keywords: v.edit tool=break
       CPU: Unspecified | Platform: Linux
--------------------------+-------------------------------

Comment (by GG12345):

Hello and Happy Christmas to all !
Sorry for the delay, was doing additional testing.

This bug seems to like Xmas time...
I reopened the ticket because I still have the same artifacts on 7.0.2.

Below is a simple way to reproduce the bug :

In a location based on EPSG:27572

{{{
v.in.ogr --overwrite -o input=/.../test_break_lines2.shp output=ptnet
v.edit --verbose --overwrite map=ptnet layer=1 type=line tool=break
coords=531934.28,1851818.17,531949.15,1851831.79 threshold=0.01
v.out.ogr --overwrite -cs input=ptnet olayer=ptnet format=ESRI_Shapefile
type=line output=/.../test dsco="SHPT=ARC"
}}}
Data is attached.

v.edit behaves differently depending on the precision of breaking
coordinates. For the following examples I used only one point to break the
lines.
- With 8 decimals (531934.283798572,1851818.16932773) it selects the
features but does not brake them. Debug=3 shows that spdist value of
Vect_line_distance is 0 which is wrong. I wasn't able to track the bug
further.
- With 2 decimals (531934.28,1851818.17) it selects 2 features but breaks
2 which is wrong
- With 3 decimals (531934.283,1851818.169) it selects 3 features and
breaks 2 which are both wrong

Is it the same bug as for 6.5 ? Any solution ?

Thanks for the help !
Cev.

g.version shows :
{{{
GRASS 7.0.2 (2015)
PROJ.4: 4.8.0
GDAL/OGR: 1.10.1
GEOS: 3.4.2
SQLite: 3.8.7.1
}}}
g.proj shows :
{{{
-PROJ_INFO-------------------------------------------------
name : Lambert Conformal Conic
proj : lcc
ellps : clark80IGN
lat_1 : 46.8
lat_0 : 46.8
lon_0 : 0
k_0 : 0.99987742
x_0 : 600000
y_0 : 2200000
towgs84 : -168,-60,320,0,0,0,0
pm : paris
no_defs : defined
-PROJ_EPSG-------------------------------------------------
epsg : 27572
-PROJ_UNITS------------------------------------------------
unit : meter
units : meters
meters : 1
}}}
g.region shows :
{{{
projection: 99 (Lambert Conformal Conic)
zone: 0
datum: towgs84=-168,-60,320,0,0,0,0
ellipsoid: clark80IGN
north: 1
south: 0
west: 0
east: 1
nsres: 1
ewres: 1
rows: 1
cols: 1
cells: 1
}}}

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Ticket URL: <https://trac.osgeo.org/grass/ticket/719#comment:18&gt;
GRASS GIS <https://grass.osgeo.org>