3

Tried really much to correct these errors, but v.clean can't detect them as errors.

I have a big ring polygon which is connected by bridges with 0 width

enter image description here

Is there a possibility to split this ring polygon automatically and delete this "lines"? I can't delete them manually because my file has over 80,000 polygons with everyone more than 10,000 points (It's a huge file). This file comes from a calculation programme, so I can't change really much. Also there is next to this polygon another polygon which shouldn't overlap

Maybe its possible to split the polygon in triangles and delete all with no area. Then merge it again?

I could fix this through the original Programm i exported it. But i am still interested if there is a possibilty to fix this in QGIS. If there is an option to split the polygon into triangles it could be fixed easily

nmtoken
  • 13,355
  • 5
  • 38
  • 87
ThomasT
  • 41
  • 2

1 Answers1

1

Split into squares by one of these methods:

  • Use the Gridsplitter plugin to split the entire layer along a square grid.
  • Create a square grid using Vector menu > Research Tools > Vector Grid tool. Use the Digitizing Tools plugin to split selected polygons using the grid layer. More details on this method here: Cut polygon shapefile by line shapefile

Next,

Select by expression

$area < 0.001

Make sure no polygons that you want to keep are selected. If they are, clear the selection and repeat with a smaller area value. Delete selected polygons.

Re-combine polygons by either of these methods:

  • Vector menu > Geoprocessing > Dissolve
  • Advanced Digitizing Toolbar > Merge Selected Features

Another solution: apply a buffer of 0 width. If this doesn't work, it means the bridges have a non-zero width. In that case, apply a buffer with a very small negative value.

csk
  • 24,827
  • 3
  • 32
  • 70