If the user is clicking on a data point on a map, then the latitude/longitude values for that point could be used to update parameters via Parameter Actions (added in Tableau Desktop 2019.2)
You could also add annotations to the map to find the lat/long coordinates of any arbitrary point. But the user would have to know how to create the annotations, and then they would have to type in the coordinates into parameters (copy/paste won't work). See Find Background Image Coordinates - Tableau
The Tableau website has an Ideas section where customers can add, comment, and vote on features they would like to see in the product. Votes are used to help prioritize new features. Our Development team also loves to see everyone's use cases in the comments, which helps them better design features that will meet the most possible needs.
I found the following Idea that may be of interest Mode to "annotate points" in bulk
Hope this helps
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I'm getting the impression that you want a user to simply click anywhere on the map and the Latitude/Longitude would update along with any near data points? That's not currently feasible at all.
For now, the points would have to be there to begin with and a user could then click on a point and the Latitude/Longitude parameter would update automatically thereafter, using Parameter Actions, to display related points based on a distance filter or some other filter.
I recently did something (page 2 of the thread) that might be similar or useful to you: Maps - Mileage
You could change the single parameter to use Parameter Actions with that and then build it out to use two separate Parameters, one each for Latitude/Longtiude. Best, Don
Thank you for your response. The issue stymies me is that I'm there is no mark for a user to click. I want the coordinates of where the user clicked on the map (or graph). This may work if there is a way to tile the map with invisible marks that get selected by a click, then the selection is automatically cleared. My thoughts are that in this way it should be possible to get a rough approximation of where the user clicked that could be utilized through an action which changes a parameter.
Thank you for your response. Your impression is correct. I did see the "Maps-Mileage" topic/discussion and that will not work, since the (lat,lon) of the two point are still required and I know only one of the points not where the user clicked. If I did get the two point's coordinates I would have to use the formula mentioned in the "Maps-Mileage" topic/discussion.
You might find this useful
If you scroll down to the "Map Overlays" section this does something very similar to what you want ....however Ken's map has data points for all the cities in the US, which is how it works (along with Parameter actions)