All true, @fffffffff , but I think of minor importance. Probably a smaller apparent distortion than the facts that the Oregon city of Corvallis and the Russian City of Moscow both looks like the centers of abundance for most organisms that people post of iNaturalist or donate to natural history collections. Or the apparent concentration of most species along roads, where people definitely concentrate. These are just more things people using iNaturalist (or herbarium) data have to think about, preferably before analysis.
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Right, those are different scales of same problem, especially if there’re not many plants to observe at all, but I hope % of same plants observed overall is not that high, it’s usually big old trees that get attention. With that I hope that usually when you look at map, even though it reflects one user’s action, it also depicts mostly different individuals (so chances are higher to find another one), but it’s another thing to always keep in mind when using iNat. There’s a Velvet Scoter with damaged wing and it moves on the river back and forth throughout year, so you could guess that city is filled with those rare ducks, especially with obscuring of species going on.
Yes, I can believe the range of rare things can be exaggerated a lot! (Although, in a sense, that duck crossing back and forth is outlining its range there.) There are lots and lots of dots for cultivated plants (not marked as such) at or near schools, too. The same individuals uploaded dozens and dozens of times.
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We need to move to that topic about iNat bias 
, common species are very affected too, easiest example is Mallard with 250+k of observations and big chunk of its range have no observations (and people live there), or who knows how many species have no observations in this range, when about similar area in Sahara has around 2k observations, which is still very low, but 100 times more.
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This kind of bias is not restricted to iNat either, it occurs with herbaria as well (unless they’re doing specific studies). For example, in my area the herbarium has 26 specimens lodged for Eucalyptus campanulata and 25 for E. codonocarpa for my region. This tells me nothing about abundance even in a rough sense. E. campanulata is common and very easy to find; E. codonocarpa is uncommon and considered near threatened. So looking at just the number of specimens lodged with the herbarium (call them observations) is misleading. I think it’s the same bias as can be seen on iNat and it’s not a bad thing, as you know, it’s just something to be aware of. I think we’re on the same page here and I’m certainly not disagreeing with you, I thought I’d just add another example :)
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Sure! It’s very interesting to see how iNat data is “behaving” the same way strict scientific collections do!
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