This is a Mozilla Firefox Add-On which helps you to open another map from the current map view or from a georeferenced website.
Exemplary use cases:
- You visit OpenStreetMap and want to know what this map area looks like in another map like Google Maps.
- You read the Burj Khalifa Wikipedia article and want to quickly see the location of this building on a map of your choice.
- You view a photo on Flickr and want to see where it was taken.
Now you can open that map with just two clicks using your personal list of maps
and without being limited to what the website offers you as map choice. Search
for the ShowMap toolbar icon 
It is also possible to use the context menu on a map link written somewhere in the website text. The website as a whole does not have to be georeferenced, but merely contain links to maps to make use of that feature.
This Add-On is developed with the Jetpack Add-On SDK and its jpm command line tool. Unfortunately this SDK is no longer supported and does not work in current Firefox versions (57 and newer). Mozilla has switched to WebExtensions and dropped the legacy APIs. Of course some day this Add-On should be converted to be usable with the latest Firefox version, but until then Waterfox can be used for it.
For unit testing, the Node.js based test runner AVA is used.
Run this Add-On in your browser:
jpm run
Install the dependencies locally:
npm install
Execute the unit tests:
npm test
Alternatively execute unit tests with options passed to AVA:
npx ava [<options>...]
Create an XPI package (.xpi file):
jpm xpi