Hope to obtain: sample expressions for printing each visible layer of a project using Print Layout's Atlas functionality
Based on @Erik's comments on another question (about changing QGIS behavior), I'm trying to follow through on setting up printing an "atlas."
The dialog (below) is imposing for a neophyte. The first reference returned from a search on 'atlas' in the QGIS docs is to an Example, which nevertheless is enough different from my scenario as to not shed light.
It focuses on using a vector layer composed of an array of rectangles to print a set of smaller maps covering a single layer.
In my application, I wish to use a layer with a single rectangle to print a set of maps for the same region from each of a set of 4 layers. (Erik had also suggested perhaps using a Map Theme to reference all the visual layers, but I do not find any reference to a map theme among the items available in "Expressions.")
Beyond opening Atlas->Settings in Print Layout, selecting "Generate an atlas", choosing my "Coverage layer" (with the vector layer containing my polygon), and hiding that coverage layer (so the polygon won't print on the outputs), I'm lost.
In particular, I'd like to know how to fill out:
- Configuration->PageName, ->FilterWith, and ->SortBy fields
- Output->OutputFilenameExpression field.
I'd also like to know how to get a list of the visible layers and how to step through them in Expressions Dialog (which comes up when clicking on the side-button of the PageName field). If using a map theme is the way to go, how is it referenced in the Dialog?