zoomlevel

A JOSM plugin that shows the current map view's web-map zoom level in the status bar, next to the lat/lon display.

What it shows

The zoom field displays a decimal value such as z=14.27, computed from JOSM's internal scale using the standard Web Mercator formula:

zoom = log₂(156543.034 m/px ÷ current scale)

The decimal precision makes small zoom changes visible that would be invisible as integers. Values update live as you zoom or pan.

Screenshot

Features

• Decimal zoom level — displayed next to lat/lon in the status bar
• Live updates — responds to zoom and pan with no interaction required
• Browser link — link button opens the current view in OSM or OHM, auto-detected from the JOSM API server preference (osm-server.url)
• Tooltips — hover the zoom field for "Browser-equivalent zoom level"; hover the link button for "Open OSM to this view" or "Open OHM to this view"

Installation

JOSM Plugin Manager

Search for zoomlevel in Preferences → Plugins → Download list.

Manual

1. Download zoomlevel.jar from the releases page

2. Copy to your JOSM plugins directory:

   # macOS
   cp zoomlevel.jar "~/Library/Application Support/JOSM/plugins/"
   
   # Linux
   cp zoomlevel.jar ~/.josm/plugins/
   

3. Restart JOSM and enable in Preferences → Plugins

Build from source

Requires Java 17. Uses the included Gradle wrapper.

./gradlew dist

Output: build/dist/zoomlevel.jar

Compatibility

Requirement	Version
JOSM	≥ 18877
Java (build)	17
Java (runtime)	11+
Gradle wrapper	8.5

License

GPL-2.0-or-later — see LICENSE.