I would like to graduate from a column of mine with decimal numbers. For this I want to apply the Jenks discretisation and exclude zero. I tried this, but it didn’t work…
Do you have any idea to do that?
Your query of:
I_EVEPOP > 0
Is a binary question. You are asking QGIS, is it bigger than 0. If so it will show a 1, if not it will show a 0.
What you want is a conditional:
CASE WHEN I_EVEPOP > 0 THEN I_EVEPOP END
"I_EVEPOP" > '0' should work.
Columns, when referenced in equations, need to be put in double quotation marks, any value you want to place, grab or check for in single marks.
You need to switch to Rule-based styling to remove 0 value from the classification. You can use Graduated classification first to classify your data using the desired column as it is and using
Mode: Natural Breaks (Jenks) as you can see below:
However, to remove the 0 value you need to switch to Rule-Based classification, and as you can see in the following image, the highlighted rule shows the
ColumnName >= Value. In this example
New_ID >= 0.000
You need to change it to
New_ID > 0.000 by removing the equal
= sign. But in this case the polygon with the value equal zero will disappear.