I have a shapefile with 50 Polygons. I want to create one PDF file in which I see only one polygon per page. I think I have to use the Atlas function. But I don't know how to Setup the filter.
The Atlas Filter controls which features are used to make the entire atlas. It doesn't control which features are displayed on the current atlas page.
To control which features are displayed on the current atlas page, use rule-based symbology to make feature visibility depend on the active atlas feature.
Choose a field to be the atlas page name. In my example, I used a field called "atlasfilter."
Style the layer with rule-based symbology. Substitute the name of your page name field in the following rule:
"atlasfilter" = @atlas_pagename
Generate an Atlas preview, and flip through the pages of the atlas. The current atlas feature should be the only one displayed on each page.
Notice that this rule-based style applies to the main project map as well. When you disable the atlas preview and/or close the print layout, the most recent atlas feature is still the only one displayed. If you want to see all the features on the main project map:
- Add a second rule with no filter, then toggle between the two rules depending on whether you're working on your map canvas or on the atlas.
- You can also lock the layer style in the print composer map. Once it's locked, you can change the layer style in the main map and the print composer map will stay the same.
Rather than explaining the process (badly) here are some tutorials, I used the first one but the others look good also:
https://docs.qgis.org/2.8/en/docs/training_manual/forestry/forest_maps.html https://www.qgistutorials.com/en/docs/automating_map_creation.html https://underdark.files.wordpress.com/2016/10/material_atlas_qgis_tutorial.pdf
Best of luck, come back with any specific questions.