[GRASS-user] Split polygons with lines

GRASS GRASS user
1

Hi,

I’ve been looking for ways of grass gis splitting a polygon into multiplepolygons with a line shapefile and wondering are there tools in Grass to do this!!

Thanks

···

Le gach dea ghui,

Shane Carey
GIS and Data Solutions Consultant

2

Hola, no si buscas algo parecido a esto que es en QGIS

dejo el link de acceso al video:

https://www.filemail.com/d/bspgwgmhyxruqcu?&showconfirmation=true

Saludos

Eddison

El dom., 10 mar. 2019 a las 8:39, Shane Carey (<careyshan@gmail.com>) escribió:

Hi,

I’ve been looking for ways of grass gis splitting a polygon into multiplepolygons with a line shapefile and wondering are there tools in Grass to do this!!

Thanks

Le gach dea ghui,

Shane Carey
GIS and Data Solutions Consultant

grass-user mailing list
grass-user@lists.osgeo.org
https://lists.osgeo.org/mailman/listinfo/grass-user

3

On Sun, Mar 10, 2019 at 3:39 PM Shane Carey <careyshan@gmail.com> wrote:

Hi,

I've been looking for ways of grass gis splitting a polygon into multiplepolygons with a line shapefile and wondering are there tools in Grass to do this!!

Please take a look at
https://grass.osgeo.org/grass76/manuals/v.edit.html

Markus

4

Thanks Markus, it doesnt seem to do the trick for me unfortunately.
Thanks for your help

···

Le gach dea ghui,

Shane Carey
GIS and Data Solutions Consultant

5

On 10/03/19 15:39, Shane Carey wrote:

Hi,

I've been looking for ways of grass gis splitting a polygon into multiplepolygons with a line shapefile and wondering are there tools in Grass to do this!!

Does the following correspond to what you are looking for ?

test = polygons
test2 = lines

# patch lines and polygons together
v.patch test,test2 out=test_patched

# transform lines to boundaries
v.type test_patched out=test_patched_bound

# break boundaries at intersections
v.clean test_patched_bound tool=break out=test_patched_bound_clean

# add centroids to new areas
v.centroids test_patched_bound_clean out=final

This can be easily scripted into a small addon module.

Moritz

6

Hey Moritz,

Thanks for coming back to me. I figured it out with the following script

import processing
polys = QgsVectorLayer(r"C:\Users\shane.carey\Desktop\poly.shp", ‘poly’, ‘ogr’)
lines = QgsVectorLayer(r"C:\Users\shane.carey\Desktop\s1line.shp", ‘lines’, ‘ogr’)
output = r"C:\Users\shane.carey\Desktop\split2.shp"
processing.run(“saga:polygonlineintersection”,{ ‘POLYGONS’:polys, ‘LINES’:lines,‘INTERSECT’:output})

Cheers

···

Le gach dea ghui,

Shane Carey
GIS and Data Solutions Consultant