Issue with zoom levels

General talk
1

Hi,

First post here, I’m only a very basic user. I think I should be able to state my question clearly without having to describe my use case in detail.

Basically I need to know the relative scale factor between each zoom levels.

The OSM wiki (as viewed today) lists 21 zoom levels (from 0 to 20), but I only seem to get 20:

  • zoomed out fully, the address bar shows
www.openstreetmap.org/#map=0/
  • zoomed in fully, the address bar shows
www.openstreetmap.org/#map=19/

I need to know which zoom level is missing. This is not obvious, because I can see any of the following happening:

  • level 20 is missing, the address bar uses the same level numbers as the wiki
  • level 0 is missing, and all levels have been renumbered, so when the address bar shows 0 the scale is actually what the wiki shows as 1.
  • an intermediate level n is missing, some levels have been renumbered, so
    • when the address bar shows 0 the scale is actually what the wiki shows as 0,
    • when the address bar shows n-1 the scale is actually what the wiki shows as n-1,
    • when the address bar shows n the scale is actually what the wiki shows as n+1,
    • when the address bar shows 19 the scale is actually what the wiki shows as 20.

Does this make sense? Clearly there are lots of ways to check manually but I’d like to know properly. Please let me know if any clarification is required.

2

Zoom level 20 does not exist on the standard layer on OSM.org, but it exists on the cyclemap and transportation layers, which even go up to 21. The humanitarian map goes to 20.

3

It’s 2

Those are just numbers. Clearly you could add higher or lower zoom levels as well, though of course a “zoom level -1” isn’t much use unless you’ve got a larger planet than earth.

Some maps show higher zoom levels - https://map.atownsend.org.uk/maps/map/map.html#zoom=24&lat=52.73955894&lon=1.08268578 is an example of somewhere at zoom level 24. That’s a tiled raster map like OSM is, but many maps these days are vector maps where non-whole number zoom levels are possible.

No zoom levels are missing. Generally speaking, if the wiki disagrees with how an implemented Leaflet map appears (like the osm.org website) then the wiki is wrong.

Although some of https://wiki.openstreetmap.org/wiki/Zoom_levels is OK, quite a lot is at the very least misleading.