Q:

Representing data on thematic map in only two colors in qgis

I am very new to qgis, and i am doing a project on representing child immunization on thematic maps.
I want to represent the data which is even number in one color and odd number data in another color, i tried representing it in a thematic map.
In the style tab of layer properties I selected it as categorized and then selected the column which I want to represent it on map and selected color in color ramp and then classified it,but I don't know how to show even data in one color and odd data in one color.

A:

You can use Rule Based Styles for this. 
Go to the Style tab of layer properties and choose Rule Based from the drop down menu (where you selected categorized before).
Click on add rule (a small plus icon on the bottom of the window) and the Rule Properties window will open, Label it as Odd, in the filter use your data column (mine was category) % 2 = 1 (odd numbers will have a remainder of 1 when divided by 2). Then set the symbology you want to apply to the style.

Similarly add another Rule, this time for Even values ( remainder 0, since even numbers will be divisible by 2 ):

Click OK and it's done.

