Questions tagged [self-intersection]

A self-intersecting polygon is where the boundary (edge) crosses over itself.

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Ring self-intersection error when running Random Points

This error occurs on two rows of my shapefile: Feature (650) has invalid geometry. Please fix the geometry or change the Processing setting to the "Ignore invalid input features" option. ...
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OpenLayers 2 - prevent self-intersecting polygon [duplicate]

OpenLayers 2: How can I detect whether a polygon (or linear Ring) is self-intersecting and how can I prevent that?
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1answer
839 views

How to fix invalid polygon with self-intersection - Python [closed]

I have a self-intersecting polygon inside a shapefile. Does there exist a Python library which spots the self-intersections and makes it possible to correct them? I have found it is possible in QGIS ...
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2answers
269 views

Finding polygon self-intersection with PyQGIS on QGIS 3.4

My script: from qgis.core import * import qgis.utils import processing, os, sys, glob polys = QgsVectorLayer("/Users/john/shapefile/layer.shp","intersection","ogr") output = "/Users/john/shapefile/...
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1answer
69 views

Determining if route self intersects using Java? [closed]

I have a sequence of coordinates (lat,lng) defining a route. How can I determine whether this route is self intersecting? I am trying to implement a Java method for this, but I have been ...
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QGIS: Dissolving Polygons with Self-Intersection

I have created multiple polygons with some subset of track-lines, with the order of time those points were recorded. Therefore some of the polygons have self-intersection within the polygon. Is there ...
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1answer
231 views

Finding self-intersection in PostGIS

I've developed an query to find self-intersection points by using PostgreSQL 10 and PostGIS 2.4 database. The query took long time (aprx 90mins) to produce the result from 3,122 polygons. The query is:...
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1answer
216 views

Command line tool to repair self-intersection in GeoJSON

I am working with this file. Kansas seems to have a self intersection: TopologyException: Input geom 0 is invalid: Self-intersection at or near point -98.918045000000006 37.379078 at -98....
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1answer
2k views

Fixing invalid geometry (self intersection)

Attempted to extract raster by mask layer in QGIS 2.18.15 and for one of my shapefiles, the command could not be executed. The error message reads "Warning 1: Ring Self-intersection at or near point ...
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1answer
114 views

Self-intersecting geometry errors when splitting polygons

I'm having issues digitising in QGIS 2.18.20 on my mac. My normal strategy for digitising a habitat survey area is to create a (shapefile) polygon for my survey boundary, and split the shape ...
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1answer
461 views

Topology exception on geometry intersection?

I am using the following PostGIS functions in a Postgres query: ST_AsGeoJSON(ST_Intersection(p.geom,c.geom)) Where p.geom & c.geom are type multipolygon. The query works most of the time but ...
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126 views

Issues with geometry in QGIS but not ArcGIS? [closed]

I have found that shapefiles that function normally in ArcGIS will not work in QGIS due to geometry issues. For example, I have a species geographic range file that when I intersect with a buffer will ...
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2answers
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Updated: Fix for Polygon Self-intersection QGIS 2.18.14?

I am attempting to mask a raster to US Forest Service boundaries in QGIS. It fails due to self - intersections of polygons. Warning 1: Ring Self-intersection at or near point -109.90112962000001 43....
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2answers
1k views

Invalid geometries made valid don't remain valid?

From https://s.geo.admin.ch/77395652c7 I got the groundwater resources data for Switzerland. (deeplink to ZIP with Shapefiles, 147.3 MB). Some areas therein are self-touching*, which makes gdalwarp ...
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2answers
187 views

How do I topologically clean “pointy bridges” using GRASS v.clean?

I have a shapefile with hundreds of pointy areas connected at the tip, forming a "pointy bridge". This creates a self-intersection and duplicate node. I'm not exactly sure what this type of error is ...
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1answer
190 views

LineString Self-Intersection points

I'm trying to get all the points from a Self-Intersection LineString. On LineString segments intersection with no vertex on intersection: ST_Intersection make the job; Now, how catch the vertex ...
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2answers
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Bowtie or hourglass polygon validity issue when self-crossing point is not defined

Using Python2.7 and shapely, let: import shapely coords = [(0, 0), (0, 2), (2, 0), (2, 2), (0, 0)] bowtie = shapely.geometry.Polygon(coords) bowtie.is_valid which gives this : Self-intersection ...
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1answer
401 views

Count the intersection of buffers, in the same layer. qgis [duplicate]

If I have one shape of buffers, How to count the number of times, the different buffers (in the same layer) intersect each other.
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1answer
2k views

How to fix polygon with ring self intersection in QGIS?

When I polygonize a raster, I very often have 'pixels' holes/interior ring that touche exterior ring. Example : POLYGON((5 0, 10 0, 10 10, 0 10, 0 0, 5 0, 3 3, 5 6, 7 3, 5 0)) It's defined as an ...
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1answer
457 views

Python - gdal.Polygonize produce invalid geometries

gdal.Polygonize is making invalid geometries and later in processing chain an error is reported stating that there are Ring Self-Intersections. Not one, quite a few so manual solution is not an option ...
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2answers
2k views

How to overcome invalid input geom and self-intersection when intersecting shapefiles in R

I downloaded two shapefiles from IUCN (available here and here) to determine the range overlap between two species. When I bring the shapefiles into R, I am able to plot them on a map together, ...
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1answer
3k views

Clipping a raster by a polygon layer: Error “Cutline is not valid after transformation”

I have a raster layer (3 cm x 3 cm) and a vector layer with polygons and when I try to clip the raster by the polygon layer to have just the bare earth/ground regions left over, so I can interpolate ...
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1answer
657 views

R: Self-intersection error when using intersect with two shapefiles

I am trying to "translate" worldwide raster data to European nuts3 polygons. That means I try to overlap two shapefiles to find the average value on nuts3 level. Unfortunately, when I use the ...
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1answer
501 views

Draw polygons from self-intersecting lines: Looking for a workaround for inner boundaries / holes

I use OGR & Python to develop a geodesic polygon buffer. The buffered polygon is generated from a polyline ring. The polyline ring is generated from point coordinates. As the polyline ring is ...
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0answers
739 views

Creating inner ring of polygon using buffered geometry in JTS? [closed]

I am still a beginner to GIS. I have a polygon and I want to draw a large border inside the that polygon (see fig A and B below). With the library I am using, I have to do this with a polygon with "...
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1answer
151 views

PostGIS help writing a ST_MakeSimple method for self intersecting lines?

I have imported Open Street Map lines into PostGIS 2.1 and I need to clean up the self intersecting ways. I have done some manual edits in the past but there are many more ST_IsSimple(way) = false ...
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1answer
55 views

Self-intersecting after exporting .shp from Personal GeoDatabase

I have a Feature Dataset in a Personal Geodatabase, with resolution = 0.00000001 and tolerance = 0.000000005. I am exporting the Polygon Feature Classes to shapefiles, after setting Resolution = 0....
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1answer
15k views

Getting TopologyException: Input geom 1 is invalid which is due to self-intersection in R?

The 'TopologyException: Input geom 1 is invalid' self-intersection error which arises from invalid polygon geometries has been widely discussed. However, I haven't found a convenient solution on the ...
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5answers
5k views

Fix Self Intersecting Polygons Manually [closed]

I are looking to implement a method to fix self-intersecting polygons by editing the vertex order. We want to take the polygon rings and re-arrange/add in vertices to make a valid polygon. This is ...