Combining Query Builder with Atlas Generation

Question

I'm using QGIS 2.16.1 - Nodebo.

I have a layer containing 200 polygons which has been styled on a categorical variable. All these polygons - constituencies, belong to regions. There are 6 regions. I want to automate making region level maps. [![enter image description here][1]][1]

Right now, I go to the query builder, and filter on a region and get the map like the one below and save it [![enter image description here][2]][2]

How can I automate tell QGIS to go through all regions and filter on that region and save that region map? (automation is what I'm looking for - through a Python script or Atlas Generation)

Answer 1

Create a temporary layer by dissolving the constituency layer by region to get a layer with six polygons.

Vector > Geoprocessing Tools > Dissolve

Uncheck the Dissolve all box and choose your region field and add it to the selected side. I left the option to create a temporary layer as is.

Use this new layer as a hidden coverage layer in the Atlas Generator. Keep the consituency layer on. Then each map output will contain all the consituencies in the region on display.