I am using GeoFacetHandler with the following distances: 1km, 2km, 5km, 10km and 25km.

The problem is that FacetSortSpec.OrderValueAsc doesn't work, because the facets will be sorted like this:

1km 10km 2km 25km 5km

Left-padding the distances with zero is a workaround but in this case you have to remove the leading zeros on rendering.

Using FacetSortSpec.OrderHitsDesc solves the problem only if the facet numbers are not equal:

All 16 25 km 16 10 km 3 1 km 2 2 km 2 5 km 2

A Custom Facet sorter could help but IMHO it can't be in the intention of the inventer that the usage of the GeoFacetHandler requires a custom sorter... What do you think?