Hi all! First of all, this is a theory I have been thinking about and really tested it out the last few days to some interesting results!
It all started during vacation. Me and the GF went out to the coast to spend the day. Far away from anything and the in game pokemon radar was total blank. Popped an incense while laying in the sun and boom, a Vulpix arrived. And then some Pokemons I have never seen before in the wild here in Sweden (Ponyta, Diglets and even two Dragonairs).
When used near civilization all I have ever gotten is the rattatas, weedles and pidgeys.
Didn’t think much about it but last week something interesting happened that triggered me to try it out. Once again we visited a very remote lake that for some crazy reason had a PokeStop out in the middle of nowhere. I popped a lure and an incense and was overwhelmed with amount of Pokemons that day. It made no sense, but I got Abras, Charmanders, Bulbasaurs, Dratinis, Vulpix, Mr Mime, Onyx and many more throughout the day.
So the theory I have been testing for the last few days is that I find a spot where the in game radar can not find a single pokemon nearby (the ingame pokeradar must be completely blank), and pop incense. And BAM, rare Pokemons just start spawning. Doesn’t matter where I am (near water, forest, etc), all different kind of Pokemons spawn.