Add aerial imagery, fixes #56

[matkoniecz]

Notes:

• it uses Esri aerial as it has a global coverage and - unlike Bing - is available without byzantine setup.
• it works, but I suspect that it is architecturally sad way of getting preferences.
• I worry a bit about this setting encouraging people to start and answering remotely and guessing "gray on aerial"? definitely asphalt! But it would be useful in some cases.
• fixes second-oldest open issue ( https://github.com/streetcomplete/StreetComplete/issues?q=is%3Aissue+is%3Aopen+sort%3Acreated-asc ) and finishes branch that I started a year ago :)

[andrewharvey]

Awesome. In the future it would be nice to use the "best" layer from Editor Layer Index, but that would be a fair bit more effort, so glad to see this launch first.

[HolgerJeromin]

Please add
fixes #56
To the first comment to be recognised by the PR gui on the right/bottom.

[matkoniecz]

To the first comment to be recognised by the PR gui on the right/bottom.

It is in the title what should be sufficient.

And likely is in one of commits already anyway.

[matkoniecz]

Awesome. In the future it would be nice to use the "best" layer from Editor Layer Index, but that would be a fair bit more effort, so glad to see this launch first.

I worry a bit about potential misuse. So sinking time into implementing all that seems to not be a good idea if it could be potentially removed anyway.

And many imagery sources require various special support, API keys, workarounds etc so it would be quite time consuming.

[FloEdelmann]

That's surprisingly little code for such a big feature!

[matkoniecz]

That's surprisingly little code for such a big feature!

I never though that I will praise Esri for making the simplest product that is available for free. But I must say that from worldwide aerial views without extra complexity - their is the best among ones available for OSM mapping.

Also, nice case of how measuring programming work by lines of code is a bad idea: that was not simple to figure out how to run it (commit history reveals it only partially).

[westnordost]

Doesn't ESRI require attribution in the corner of the map or something?

[matkoniecz]

No, see #56 (comment)