[postgis-devel] ST_UnaryUnion vs ST_Dump + ST_Union

[Jose Carlos Martinez Llario]

Dear List,
¿What are the differences between an st_unaryunion and a normal union 
aggregate with the dump geometries from the geom?
I just could see that the order of the generated segments change.
What am I missing?

In order to node a LineString with selt-intersections, I still have to 
use st_union (point, geom) because st_unaryunion does not node 
self-intersection lines.
So I do not know if this new operator is very useful.
Probably Im missing things, I didnt check it out deeply.

Best,
Jose