[QGIS-Developer] Quantile (Equal Count) broken or is data borked?

[Richard Duivenvoorde]

On 03/03/2019 11.31, Richard Duivenvoorde wrote:
>>> https://duif.net/temp/QuantileEqualCount2.png
>> I can't reproduce. Maybe data set dependant?
> I've created random data in a geopackage and created an issue for it
> 
> https://issues.qgis.org/issues/21451

Mmm, diving into this a little more (googling about Quantiles...), it
appears this has to do with ordering/ranking the data and then set 'breaks'.

So in this dataset there seems to be A LOT of values '0' so if you first
order that dataset, then create the breaks/buckets, it is possible to
have several 'buckets' in the 0 range? So this then is not so much an
error in creating the breaks, but more the visualisation of the numbers
in the classes (IF it is indeed ok, to have several 'classes' all having
0 both as min and as max value....).
Then QGIS should divide the 0-values over the 3 buckets all containing
zero's?

OR am I just misusing a method? And should you not use this method in a
dataset in which the distribution is so uneven?

Anybody more into this statistical theory then I am??


Regards,

Richard Duivenvoorde