The objective is to find the Places of Events of Ancestors of the [[Gramps_Glossary#home_person|Home Person]]. That's 4 stages of filtering.
You can set up a [[Example_filters|multi-stage of filter]] that
show only Places for Ancestors & configure the Places Category view to show the Longitude & Latitude columns. This will tell you how many of Ancestor related Places will be omitted from being plotted on the map.
For this multi-stage custom filter, create the following Cascade of custom filters: