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RuntimeWarning encountered for unary_union operations.

See original GitHub issue

I have a set of polygons:

'POLYGON ((-0.961 0.109, -0.16 -0.98, -0.782 -0.319, -0.961 0.109))',
 'POLYGON ((-0.782 -0.319, -0.622 0.661, -0.961 0.109, -0.782 -0.319))',
 'POLYGON ((-0.179 0.428, -0.961 0.109, -0.622 0.661, -0.179 0.428))',
 'POLYGON ((0.179 -0.428, -0.16 -0.98, 0.622 -0.661, 0.179 -0.428))',
 'POLYGON ((0.179 -0.428, -0.782 -0.319, -0.16 -0.98, 0.179 -0.428))',
 'POLYGON ((0.179 -0.428, -0.622 0.661, -0.782 -0.319, 0.179 -0.428))',
 'POLYGON ((0.782 0.319, 0.622 -0.661, -0.179 0.428, 0.782 0.319))',
 'POLYGON ((0.16 0.98, -0.179 0.428, -0.622 0.661, 0.16 0.98))',
 'POLYGON ((0.16 0.98, 0.782 0.319, -0.179 0.428, 0.16 0.98))',
 'POLYGON ((-0.339 -0.552, -0.179 0.428, 0.622 -0.661, -0.339 -0.552))',
 'POLYGON ((-0.339 -0.552, -0.16 -0.98, -0.961 0.109, -0.339 -0.552))'

when performing union_all() on them, 2 RuntimeWarning are generated:

polygons = pygeos.from_wkt(
      ['POLYGON ((-0.961 0.109, -0.16 -0.98, -0.782 -0.319, -0.961 0.109))',
       'POLYGON ((-0.782 -0.319, -0.622 0.661, -0.961 0.109, -0.782 -0.319))',
       'POLYGON ((-0.179 0.428, -0.961 0.109, -0.622 0.661, -0.179 0.428))',
       'POLYGON ((0.179 -0.428, -0.16 -0.98, 0.622 -0.661, 0.179 -0.428))',
       'POLYGON ((0.179 -0.428, -0.782 -0.319, -0.16 -0.98, 0.179 -0.428))',
       'POLYGON ((0.179 -0.428, -0.622 0.661, -0.782 -0.319, 0.179 -0.428))',
       'POLYGON ((0.782 0.319, 0.622 -0.661, -0.179 0.428, 0.782 0.319))',
       'POLYGON ((0.16 0.98, -0.179 0.428, -0.622 0.661, 0.16 0.98))',
       'POLYGON ((0.16 0.98, 0.782 0.319, -0.179 0.428, 0.16 0.98))',
       'POLYGON ((-0.339 -0.552, -0.179 0.428, 0.622 -0.661, -0.339 -0.552))',
       'POLYGON ((-0.339 -0.552, -0.16 -0.98, -0.961 0.109, -0.339 -0.552))'
      ])      
pygeos.union_all(polygons )

C:\ibrus-env\lib\site-packages\pygeos\set_operations.py:388: RuntimeWarning: divide by zero encountered in unary_union
  result = lib.unary_union(collections, **kwargs)
C:\ibrus-env\lib\site-packages\pygeos\set_operations.py:388: RuntimeWarning: invalid value encountered in unary_union
  result = lib.unary_union(collections, **kwargs)

I don’t know what exactly triggered this warning and if it affects the calculation result of union operations.