Don't flag very close points on different layers/levels

[quincylvania]

It's valid for features to be in exactly the same location if they vary on the z-axis.

[1ec5]

Tags to consider in this heuristic: ele, layer, level. Maybe also height for mounted features such as antennae, sirens, and flags, since it’s easier to ascertain than the absolute elevation? repeat_on is interesting but maybe nonessential for this issue.

[quincylvania]

@1ec5 I hesitate to use elevation only because I've seen overlapping points from different imports with slightly different ele values, though that's probably not very common.

[1ec5]

Oh that’s a good point. I’ve seen that happen with coincident POIs imported from GNIS. Come to think of it, it wouldn’t be unreasonable to expect mappers to use layer to explicitly avoid this warning, since that’s what avoids crossing ways warnings for bridges and buildings.