I have simple question. How can I know the original group after apply
z = sf::st_union(x, y)?
I have 2 sets:
length(x[]) = 4253,
length(y[]) = 91. Finally, I have
z of lenght 411 but don't know which polygons came from which input set,
y. At the end, I need to leave the
x group only.
Can I set some attribute for
y before union? If so how? Maybe there's simpler way to achieve it?