What is the best way to present a document map with ranges?

I have a very long document that many lines can be logically grouped into ranges. For example, maybe something like this:

cow #1
cow #2
cow #3
...
dog #1
dog #2
...
table #1
...
chair #1
...
etc.

This list can be grouped into ranges (lines 1-1000: animals, lines 1001-2042: furniture, etc.) and sub ranges (lines 1-444: cows, lines 445-678: dogs, etc.)
Since this is a long list, I want to present a quick document map type of scroll bar thing with colored areas (don't need labels) to allow quick navigation by clicking the bar. Any ideas/examples of how to do this?

Bonus What if the ranges aren't nested, so that we can have for example ranges such as 1-200, 100-150, 120-300?