Austrian background imagery: Use Esri instead of basemap for Vienna area as the default imagery

[LaszloEr]

trafficstars

ESRI uses the same imagery as basemap.at for the Vienna, Austria area, but in a higher resolution. It should be set as the recommended imagery for the town, if possible.

[simonpoole]

You would need to create a duplicate entry of the ESRI layer with a polygon restricted to Vienna for this to work technically, but I doubt that we really want to do that.

The other way to fix this is to ask basemap.at to provide the higher resolution imagery (because obviously it is publicly available there is no reason to restrict it artificially).

[grischard]

See also #691 for the same issue in Estonia.

[hlfan]

Esri uses two different imageries in Vienna, one with 8cm resolution (zoom level 21) from march 2017 as per Esri Metadata. The other one is the current yearly 15cm orthophoto provided by the city.

Here a comparison of some of the imagery at 48.1716,16.3972:

Esri imagery	Comparison
esri v2021	wien.gv.at
esri v2017 (downscaled)	basemap.at

The maximum resolution for the 2021 imagery is from every host 15cm, zoom level 20. This would also be visible in the editors, if only the max zoom value were set to 20 for the local imagery hosts. To fix this I created pr #1584.