Produce valid results when simplifying areas close to the threshold
When the simplified area extends not significantly more than the size threshold in one direction, the result of the Douglas Peucker algorithm can deteriorate into a area-less polygon. In this case we fall back to the bounding box instead now. It's not that those small features have much practical impact, but the resulting broken polygons cause problems in subsequent use.
Showing with 12 additions and 3 deletions