Print composer changes maps when I zoom out?

Question

I am making a small multiples visualization of about 32 different maps, all from the same shapefile/source using QGIS 3.0.1. I am using the "Provide feature filter" to select the data that I need to display.

I update each map, one at a time, but when I zoom out using my mouse, it completely erases all the work I've done and changed every single map to my most recent filter selection.

Prior to zoom: This is what it all changes to as soon as I zoom out:

In some of the maps, as soon as I zoom out, they lose the ability to "lock layers."

I tried "lock layers" as well as "lock layers" and "lock styles for layers." I've tried using the same CRS for every map as well as selecting "draw map canvas items."

I am at a complete loss.

Answer 1

I think that what you experience is due to the fact that the provider feature filter act as the provider level so you could access only the data that are not filtered. When you change the filter the other map can't access any other feature anymore and zooming cause every map to refresh and load only the last filtered feature.

One thing you could try is to duplicate the layer 32 time then set the appropriate filter to each of your 32 layer and define 32 map theme (one for each of your map) with the relevant layer displayed and the other hidden. Then in composer you set each map to follow the appropriate map theme.

Another way of doing it could be to not filter the layer but to use transparent or no symbol symbology to "erase" the feature you dont want displayed you could then lock it for each map (I also suggest to save the 32 resulting style as it will be easier to make any modification or just cycle between each of them in main canvas)