difference between combine_points and combine_polygons_below ?

[etienneJr]

It seems to me that the philosophy behind combine_points and combine_polygons_below is very different :

• when using combine_points: true, there is no loss of information. The points are merged in a MultiPoint, so you can unmerge it and get the original list of points . source
• but when using combine_polygons_below, there is loss of information, since neighbouring polygons are unioned in a larger polygon. So you can not unmerge it to get the original polygons. source
  • (side question : I didn't understand if disjoint unioned polygons where also merged in a MultiPolygon)

Could you please confirm this ?

[systemed]

Yes, that's correct.

[etienneJr]

Thanks for the confirmation !
And I also found the answer to my side question : polygons are also merged into a MultiPolygon.
for example here in Strasbourg, with combine_polygons_below: 15, all buildings of the tile are merged into a single element.