As a geographer, I like this idea and I appreciate your introducing me to time geography!
Without tackling the idea of time geography (yet), are you primarily looking for something to:
- map multiple notes as individual location points, or
- map multiple items from a single note
For item 1, I’m imagining it something like Day One’s map view of journal entries:
This looks to be generally possible already with the obsidian-leaflet-plugin (github/forum).
There is opportunity to expand on this plugin (or create a new one) to have an “add my current location to this note’s frontmatter” function (either manually or automatically on note creation) and a dedicated pane to show a map view of your notes (as opposed to showing them on a map embedded into a separate note). It would be great to have a map view of notes that’s as integrated as file explorer or graph view. I believe this would also answer @esm90’s request.
@valentine.195, would you want to tackle this 
in your plugin, or do you feel it’s out of scope? If you’re not interested, I’ve already got my wheels spinning on the idea.
Item 2 can also be accomplished with obsidian-leaflet-plugin.
It sounds like the OP in the reddit post was looking for item 1. Do you have other use cases than my two items?
Time geography visualizations sound very interesting and also very complex. Like combining obsidian-day-planner with a map. My gut feeling for visualizing space and time in Obsidian would be a 2D map with an animation or slider to show changing time. It may not be ideal for some use cases, but I imagine it being easier to build, with more packages/libraries to take advantage of.