iPad Locations, Precise Location Off vs. On?

Current License: CC BY-SA 4.0

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Jan 27 at 17:05	comment	added	jksoegaard		1) Documented for app developers by Apple. 2) Yes, ofcourse the error is a direct byproduct of the way Apple maps the earth. That's directly what I wrote in my answer, and as I described in my answer, it is very intentional that it is built that way.
Jan 27 at 9:29	comment	added	Avana		OK, that is understandable, but if it isn't too much to ask, I would still like to know: 1. where this figure of 1-20km came from originally (is this your observed/measured experience or in the documentation somewhere), and 2. if the 1-20km margin of error you mention is a direct byproduct of the way Apple maps the spherical surface of the earth—for example with Google S2, depending on the latitude, cell levels 13 to 9 represent approximately a margin of error of ~1 to ~20 km, respectively.
Jan 19 at 11:22	comment	added	jksoegaard		I did not intend my original post to only "make it seem" that the accuracy of user device location is based on Apple's mapping when in reducedAccuracy mode". That is actually how it is. I have described in my original post what the concrete dimensions or margin of error is (1-20 km) and also that it does indeed change geographically. I cannot in my answer describe the globe in such a detail that you would know the exact mapping of all cities in the world, I'm sorry.
Jan 18 at 18:44	comment	added	Avana		I am not interested in creating my own mapping, for any reason. I am interested in what Apple's mapping is, because your original post made it seem that the accuracy of user device locations is based on Apple's mapping when in `reducedAccuracy` mode. The entire point of this question is to get a sense of what this `reducedAccuracy` is, in concrete dimensions (or within some margin of error), and—if it changes geographically, as you've implied—how and where it does so.
Jan 16 at 22:25	comment	added	jksoegaard		That mapping is created by Apple. The details of Apple's mapping is not exposed to the app. It does not mean that you cannot create your own mapping in your own app.
Jan 16 at 18:09	comment	added	Avana		You wrote "Apple has mapped the globe into a number of cells". Therefore I took that at face value to mean that it was not up to the developer, but instead a mapping created by Apple themselves. If this is the case, as your answer implies, I am interested in what method they are using, because that would determine the dimensions of the cells (geohash = rectangular, while quadtree = square) and the way in which they are organized.
Jan 16 at 15:43	comment	added	jksoegaard		How would it matter to you which algorithm they use? - It is completely transparent to the developer. You can use any algorithm you want as an app developer for your own mapping purposes.
Jan 16 at 14:55	comment	added	Avana		Thank you for your answer @jksoegaard, this is exactly the kind of info I am looking for. Is this data available in the Apple Developer docs somewhere? When you say "1-20km" for accuracy, are you referring to the range in the size of cells that they are using to map the spherical (well, as modeled) surface of the earth? Do you know which algorithm they use to accomplish this? Simple geohashing or quadtree-based? Do they use z-ordering or Hilbert Curve to represent 2D areas on the sphere as an ordered, 1D list of IDs? Do they use Google S2? Or is it just an arbitrary, proprietary mapping?
Jan 14 at 18:16	history	answered	jksoegaard	CC BY-SA 4.0