[mkgmap-dev] nearby-POI: What to do with several POI arranged on a circle?

Thu May 7 14:21:59 BST 2020

Perhaps averaging the latitude and longitude coordinates of all the 
points separately would work. That is not quite the same as meet in the 
middle. If the points are evenly spaced around the edge of a circle, 
even though the latitude and longitude scalings (except at the equator) 
are not the same. What I believe you are trying to do is minimize the 
total distance from the selected point to the collection of points.

Randolph J. Herber

On 5/7/2020 2:42 AM, Gerd Petermann wrote:
> Hi all,
>
> while doing further tests I've found this edge case (see attached file)
> Draw a circle with a diameter of ~56m and tag all nodes amenity=bank.
> The default style has
> amenity=bank [0x2f06 resolution 24]
>
> With --nearby-poi-rules=0x2f06:30:merge-at-mid-point one might expect a single POI in the middle of the circle, but the result is different:
> Since there is no POI near the center of the circle the current algo finds 4 groups, all close to the edge of the circle.
>
> I think for merge-at-mid-point I need a different algo. I'm looking at https://en.wikipedia.org/wiki/Cluster_analysis now.
>
> Gerd
>
>
>
>
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