Javadoc
Parsing GML we often end up with empty attributes that will break shapefiles
and common processing algorithms because they introduce bounding boxes (boundedBy) or hijack
the default geometry property (location). We sanitize the collection in this method by
removing them.
It is not the best approach, but works in most cases, whilst not doing it would break
the code in most cases. Would be better to find a more general approach...