Please explain this function

[G3S]

hi,

I was looking to do heatmaps and found this video.
https://www.youtube.com/watch?v=P3hmHiUfxPM

the function shown there is the following (I have changed the colours to what I need): 

=ColorMix2(
(hrank(total column(1))/(NoOfColumns(total)/2))-1,
rgb(255,102,102) // colour for max
rgb(76,101,0) // colour for min
rgb(255,255,153) // colour for middle
)

Appreciate if someone can clarify the section in blue. I am not understanding why it is being divided by 2 and then minus 1. 

thank you in advance

[ajaykakkar93]

Hi,

NoOfColumns() function returns the number of columns in a pivot table's current row segment. The ColumnNo and NoOfColumns functions are only relevant to pivot tables.

Alternate link : https://community.qlik.com/t5/Qlik-Sense-Documents/Qlik-Sense-Color-Range-Theme-Approach/ta-p/149102...

This formula assigns a value in the range of -1 to +1 as required for the 3 color approach based on your expression identified in column(1) of the dataset. I.e. the second field of your dataset which is typically the first measure after a single dimension field.

ill follow the post for more clarity from others also 

[G3S]

Thank you. what is the purpose of dividing by two?