Missing expected copyright notice for 3rd party use

[mikehaertl]

I'd like to add the tile URLs to the leaflet-providers plugin of the leaflet map library.

I could not find a clear statement what the expected copyright note should include. I only found an example on https://opentopomap.org/ where they have "© lonvia". So I would add something like this:

Trails:
&copy; <a href="http://waymarkedtrails.org">lonvia</a>
(<a href="https://creativecommons.org/licenses/by-sa/3.0/">CC-BY-SA</a>)

Is this sufficient?

[lonvia]

Please attribute to OpenStreetMap and waymarkedtrails.org. So similar to other layers you have:

'Map data: {attribution.OpenStreetMap} | Map style: &copy; <a href="https://{hiking,cycling,...}.waymarkedtrails.org">waymarkedtrails.org</a> (<a href="https://creativecommons.org/licenses/by-sa/3.0/de/deed.en">CC-BY-SA</a>)'

[mikehaertl]

@lonvia Thanks, I've updated the attributions accordingly (see here: mikehaertl/leaflet-providers@f8326c1)

But I found that it quickly gets quite lengthy and repetitive:

• Is attribution to OpenStreetMap really always required? If e.g. OpenTopoMap is used as base layer it already adds that notice. (On the other hand it would be missing if another provider is used that is not based on OSM.)
• Could you maybe live with only one generic link to https://waymarkedtrails.org for all types instead of the specific links for each variant (hiking.waymarked...)? This would prevent a lot of repetition if more than one variant (hiking, cycling, riding,...) is added.

BTW you can preview the current providers and how the attribution is composed for multiple layers here: http://leaflet-extras.github.io/leaflet-providers/preview/index.html

[lonvia]

Yes, the attribution to OSM should be there, but having it once would be enough. So, ideally you would have a way to deduplicate the 'Map data' part. And also you need of course attribute waymarkedtrails only once (in which case it might indeed be better to link to https://waymarkedtrails.org instead of the subdomains).

If space is sparse, you could shorten to: &copy; <a href="https://{hiking,cycling,...}.waymarkedtrails.org">waymarkedtrails.org</a>/{attribution.OpenStreetMap}

[mikehaertl]

Great, I've gone with the middle way now:

Map data: {attribution.OpenStreetMap} | 
Map style: &copy; <a href="https://waymarkedtrails.org">waymarkedtrails.org</a>
(<a href="https://creativecommons.org/licenses/by-sa/3.0/de/deed.en">CC-BY-SA</a>)

So full attribution to OSM and only one attribution to waymarkedtrails using the main domain for all variants.

PR to the leaflet-providers plugin linked above. Thanks for your help.