6

Does exist some plugin with it is possible to Splitting lines at a specified distance in Qgis?

4
  • I want to know if there is a plugin/tool in Qgis, that let me cut lines of a shapefile where the points of another shapefile are. Thanks in advance! Commented Apr 21, 2015 at 14:57
  • This does not really answer the question. If you have a different question, you can ask it by clicking Ask Question. You can also add a bounty to draw more attention to this question once you have enough reputation.
    – Brad Nesom
    Commented Apr 21, 2015 at 15:32
  • I have similar problem, I know there is a tool called v.split.length (using QGIS 2.18.6) and I have road layer and need to split these roads to 5 km segments. I dissolved this layer to road types first so have only 3 different types. But unfortunately it didn't work. When I dissolved whole layer to one "single" line with 1 attribute I got same result. What this tool created was thousands of line divided by junctions (with different line length). It there any way how I can avoid this and really split line by 5 km segment? Please see attached screenshot. Blue lines are C roads, blue are B roads
    – DrottTom
    Commented Mar 8, 2018 at 14:33
  • If you have a new question, please ask it by clicking the Ask Question button. Include a link to this question if it helps provide context. - From Review
    – LaughU
    Commented Mar 8, 2018 at 15:02

3 Answers 3

6

i think you can do this with Grass. vsplit or v.to.points works for you what you want...

v.split - Split lines to shorter segments. 
v.to.points - Create points along input lines in new vector with 2 layers. 

i hope it helps you...

2

Not a QGIS specific solution but I have a solution for the same problem using Python. The recursive function below break_line_max_length() takes a Shapely.geometry.LineString object and a distance value and returns a list of Shapely.geometry.LineString objects all of which has a maximum defined in dist argument.

from shapely.geometry import Point, LineString

def break_line_max_length(line, dist):
    if line.length <= dist:
        return [line]
    else: 
        segments = cut(line, dist)
        return [segments[0]] + break_line_max_length(segments[1], dist)

def cut(line, distance):
    # Cuts a line in two at a distance from its starting point
    # https://shapely.readthedocs.io/en/stable/manual.html
    if distance <= 0.0 or distance >= line.length:
        return [line]
    coords = list(line.coords)
    for i, p in enumerate(coords):
        pd = line.project(Point(p)) 
        if pd == distance:
            return [
                LineString(coords[:i+1]),
                LineString(coords[i:])]
        if pd > distance:
            cp = line.interpolate(distance)
            return [
                LineString(coords[:i] + [(cp.x, cp.y)]),
                LineString([(cp.x, cp.y)] + coords[i:])]

Example below:

>>> line_projected_crs = LineString([(964139.3529438695404679, 330222.9610171869280748), (964126.7161474197637290, 330216.1643494611489587), (964117.1236193983349949, 330210.6046891564619727), (964098.2156902365386486, 330199.1644833349855617), (964090.6063651703298092, 330194.5823128472547978), (964059.9382855900330469, 330176.2232018694048747), (963946.7483211233047768, 330109.7633781027398072), (963935.4178772714221850, 330103.7357962326495908), (963928.8533927279058844, 330100.1263311330112629), (963858.3536400874145329, 330057.5496864024316892), (963823.2569981947308406, 330036.5799001286504790), (963720.0721067255362868, 329974.9035306648002006), (963692.6907952920300886, 329960.0797074790461920), (963684.2196246678940952, 329955.5032849358394742), (963622.0352077478310093, 329916.8891303183045238), (963536.0845779583323747, 329861.5464295161655173), (963496.7778069525957108, 329833.3472477410687134), (963432.1966278479667380, 329789.1737683381652460), (963422.1127361512044445, 329781.4047729316516779)])
>>> line_projected_crs.length  #842.7394213492003
>>> line_segments = break_line_max_length(line_projected_crs, 100)
>>> for i in line_segments:
...     print(i.length)
100.00000000001499
99.99999999996642
100.0000000000037
100.00000000003674
100.00000000002392
100.00000000001194
100.0000000000049
99.99999999999824
42.73942134913942
2

QGIS 3.36 has a processing tool called Split lines by maximum length which splits a line vector by a given distance in whatever units one chooses.

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