Add IGN France baselayers and overlays

[sylvainavelo]

Hello,

Since summer 2021, IGN France web services are accessible without key (as it used to be for years).
Lists in french : https://geoservices.ign.fr/services-web-experts

I suggest to add baselayers such as aerial pictures, a base map and an overlay with administrative boundaries. All of those are WMTS tile layers compatible with brouter map display.

The idea comes from a french cyclist requesting a way to add french departments boundaries on BRouter, and using an IGN WMTS layer is a possible solution : https://twitter.com/sylvainavelo/status/1462853551139524615

It will be very much like what has been done for Swisstopo baselayers (#402).
I've seen and I understand the concern about adding non-OSM maps.

I'm working on the issue but will submit the PR only if it meets approval.

[nrenner]

What are the usage terms though? E.g. in Germany official maps are often open for private use but not for embedding in map services.

I don't see the use case or general demand for admin boundaries, so I would rather not want those.

[sylvainavelo]

Usage is free for any use, including commercial, under the terms of this license : https://www.etalab.gouv.fr/wp-content/uploads/2018/11/open-licence.pdf
Like a CC-BY, mentioning paternity is required.
And also the date of last update... But as it is a web service, I can't figure out how this can be achieved. It's probably a minor concern.

The license is clear for the data itself but it lacks information specific to web services. How much can you request the service ? (in terms of requests per minutes). I can't find. The Swiss give that information quite clearly here for instance. I will ask for details.

[nrenner]

I will ask for details.

Have you asked?

Not sure that would help much, as we can't really tell or control what our usage would be.

[sylvainavelo]

Yes I asked and it took some time to have this answer. Sorry for the late follow up :

• They contact users individually when they have clues on how to find them if their usage is dangerous for their infrastructure.
• They block IPs if necessary but not automatically.
• On their current infrastructure, it is time consuming to track users that have an unfair usage.
• They are aware that in most cases, the client application has no mean to track unfair usage as well.
• Use in an application with 10 000 users a day would be fair use (I am surprised they said users per day and not a metric using the number of requests). That seems not very specific.

[nrenner]

Use in an application with 10 000 users a day would be fair use

Sounds like a lot, we probably won't reach that with a country-specific layer that needs to be configured.

What layers should we add? A recent thread was about IGN Scan25 (requires a key) and IGN Plan25.

[sylvainavelo]

I pushed 2 base layers. That's actually an old thing I did when submitting the issue.

That's a start. I will later have a look at the Scan25 layer which is a lot richer than the one I added.

[nrenner]

I guess the Scan25 layer requires a key. Please provide instructions how to obtain one with a PR or send me a key with private mail.

You can prepare an empty entry in keys.template.js and search for usage examples using the names there.

[nrenner]

I'm going to add short names for the map link, cause they're too long for mobile screens, would those be Ok:

• IGNF Photos
• IGNF Plan
• IGNF Topo

[sylvainavelo]

Yes, those are ok.
Sorry I didn't pay attention to the mobile look.

[nrenner]

No worries, very minor issue and only in combination with overlays.

I think we can close the issue?

[sylvainavelo]

Yes sure 👍