Demo: Fixing invalid geometries

fix_geometry.py

# encoding=UTF-8
"""fix_geometry.py"""

def doit(original_geometry):
    if not original_geometry.IsValid():
        if 'POLYGON' in original_geometry.GetGeometryName():

            # Geometries that are only self-intersecting can be fixed by
            # Buffering by 0.
            buffered_geom = original_geometry.Buffer(0)
            if buffered_geom is None:
                # If a geometry does not form a closed linear ring,
                # buffering by 0 will return ``None``.  If this happens,
                # we can close the ring and then buffer by 0 again.
                closed_ring_geom = original_geometry.Clone()
                closed_ring_geom.CloseRings()

                if not closed_ring_geom.IsValid():
                    buffered_geom = closed_ring_geom.Buffer(0)
                else:
                    buffered_geom = closed_ring_geom

            fixed_geometry = buffered_geom

            if not fixed_geometry.IsValid():
                LOGGER.warn(
                    'Attempted repair of invalid geometry of feature '
                    '%s failed. Using as-is.', feature.GetFID())
        else:
            LOGGER.warn(
                'Geometry of feature %s is invalid but no repair method '
                'implemented. Using as-is.', feature.GetFID())
            fixed_geometry = original_geometry
    else:
        fixed_geometry = original_geometry
    return fixed_geometry