Union features intersecting several tiles

[drnextgis]

Is it possible to union features based on feature id values (FID)? It seems like "Merge tiles" doesn't respect that property. From here:

Although, you could use the id field in the protobuf to store information necessary for reconstructing polygons.

[mnboos]

If it was a feature id, that would really be unique per feature (even across tiles), then it would be possible and would even make more sense, than the current implementation. Currently, I merges based on location (i.e. overlapping), which is not only slow, but also error prone.

Unfortunately, the specification isn't really specific. Additionally, the feature id is optional.

[drnextgis]

I see. But the idea is to take into account feature IDs if they are existing.

[mnboos]

So the feature ID is unique per feature but same across tiles?

[drnextgis]

Exactly.