There are filtering fields 
The group "Industry affiliation" -> There is a principle there (Chemical affiliation = 1, Mechanical engineering = 2, Metallurgy = 3, etc.).
Some points in the affil parameter have a single value in the array, for example, 2 - (filtering with this value works fine), and somewhere there are many of them, for example [2, 3, 4, 5], the point is hidden because will not be sampled.
The sample works like this.
Question: How to make a selection with a parameter, where an array with several options is indicated?
How it should work:
For example, select "Industrial Parks" is type=9 .
And choose "Chemical affiliation" - this is affil=2 , but we have an array [1,2,3,9,8,6,4] , and this point is shown, because in the array there are 2 . And we also click "Mashinostroenie" this is affil=3 , we have this point to burn, because selected fields that are in the array.
You can see here The page itself
