What is the best way to let the user select a distance for a layer?

Question

So I am creating a layer list using d3 and I have a question about how best let the user select distances.

To give some background, the user will be selecting a geographic layer and will then be asked to select between 4 distances based on how far they think they are from the geographic feature based on a photo (Near, Far, Very Far, Distant). These distances will be the same for all of the layers. Currently, I've thought of two solutions, but I'm not sure which is a better approach or if there is something else entirely.

1. The first would be create another level in the layer list and then let the user select from the dropped down options.

or

2. Have a pop up window appear each time a layer is clicked that allows the user to select between the 4 options.

Which makes more sense? My initial thought would be the first option as it's less intrusive, but is there a reason to use a pop up? Any suggestions are greatly appreciated.

Answer 1

First approach of showing options in another child layer is better, since context is preserved or easy to understand, compared to showing the those 4 options in a popup(title of the popup may give the context, but not inline context).

For, first approach if the options are limited to only four it may be better to use ratio buttons instead of combo dropdown, which needs 2 click for a selection.

Assumption:- In case user is selecting several layers like a locality in a city in a country in a continent, then he has to handle 4 popups.