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I have a polygon layer (Geopackage with 378 features in EPSG:3857) with many very small gaps between them (topology checker lists more than 5000). The gaps are in a range of several hundred meters to fractions of millimeters in map units (meters). Using QGIS 3.16, I tried Grass v.clean. However, it is not able to repair the geometries. No output is generated.

Error messages in the protocol mention:

ERROR 1: osgeo::proj::io::WKTParser::Private::buildEllipsoid: non double value

WARNING: Unable to determine input map's vector feature type(s).

ERROR: Unable to create OGR spatial reference

I tried also QGIS native repair geometries as well as fill gaps algorithm - the resulting output has the same gaps.

What else could I try to remove these gaps?

Taras
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Babel
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    Have you looked at the answers to the question: Filling holes in polygons automatically using QGIS? – ahmadhanb Nov 16 '20 at 10:52
  • Can you please share a sample of those polygons with us? Are you running QGIS with GRASS GIS or simply pure QGIS? Are those geometries polygons and multipolygons? – Taras Nov 16 '20 at 12:03
  • Also its important, which version you use. Not all processing tools are working in every version, not even in the newest :O e.g. we use a processing tool which only works in 3.12... – The Rabbit Nov 16 '20 at 12:35
  • I use QGIS 3.16 with GRASS GIS on win 10. I played around with the settings and was finally able to remove the holes when I used the original Shapefile in EPSG:4326 instead of the Geopackage in EPSG:3857 I used initially. I also used the settings Input feature type=area, Cleaning tool=rmarea, threshold=90000. So with the "original" shapefile it works, but not with the Geopackage – Babel Nov 16 '20 at 13:18
  • Works: INFO processInputs Ende. Befehle: ['g.proj -c proj4="+proj=longlat +datum=WGS84 +no_defs"', 'v.in.ogr min_area=0.0001 snap=-1.0 input="my_path\shp\shs.shp" output="vector_5fb2795601c5813" --overwrite -o', 'g.region n=46.87657769 s=40.8536596 e=23.034051 w=13.67744783', 'v.clean input=vector_5fb2795601c5813 type="area" tool="rmarea" threshold="90000" output=output73ee3da8d16c4a3480a9360bee4c5765 error=error73ee3da8d16c4a3480a9360bee4c5765 --overwrite'] – Babel Nov 16 '20 at 13:23
  • Does not work:

    INFO processInputs Ende. Befehle: ['g.proj -c proj4="+proj=merc +a=6378137 +b=6378137 +lat_ts=0 +lon_0=0 +x_0=0 +y_0=0 +k=1 +units=m +nadgrids=@null +wktext +no_defs"', 'v.in.ogr min_area=0.0001 snap=-1.0 input="my_path.gpkg" output="vector_5fb278c35228312" --overwrite -o', 'g.region n=5921951.62716076 s=4990780.39183815 e=2564138.82822629 w=1522566.52778716', 'v.clean input=vector_5fb278c35228312 type="area" tool="rmarea" threshold="90000" output=output242512c6a24c47589601c33ba2e8d09f error=error242512c6a24c47589601c33ba2e8d09f --overwrite']

     – Babel Nov 16 '20 at 13:24
  • Just tested: reproject the gpkg in EPSG:3857 to gpkg in EPSG:4326: like this, it works. It's quite strange: shouldn't i work with projected CRS as well? – Babel Nov 16 '20 at 13:31

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