Tallinn city has released a web page with some information about Tallinn. Its probably possible to use as a tool for us I presume to improve map where possible.
Before using any map data we need to understand under what license it’s distributed.
It’s Creative Commons Attribution 3.0 Unported
We’d need to ask a specific permission.
https://blog.openstreetmap.org/2017/03/17/use-of-cc-by-data/
Maybe it would make sense to even ask to require a special permission for OSM for all new datasets if they like CC that much.
Some time ago I discovered that Tallinn offers geospatial data:
And the map data actually differs from what is available in Maa-amet.
But to me it is not clear if this license allows to use it as a source for OSM:
These points are a bit suspicious. Is it enough that OSM as data will have the source? What about maps produced based on it, like osm.org? Maybe this OpenStreetMap should be updated then.
- Litsentsisaaja kohustused
3.1. Litsentsisaaja kohustub andmete avaldamisel ja edasi levitamisel viitama andmete päritolule, märkides ära litsentsiandja nime, andmestiku nimetuse ning andmete vanuse. Näiteks: “Tallinna aluskaart: Tallinna Strateegiakeskus 2021” (inglise keeles “Tallinn Basemap: Tallinn Strategic Management Office 2021”).
3.2. Litsentsisaaja kohustub andmete edasi levitamisel andmetega kaasa lisama käesoleva lepingu teksti või viite lepingu tekstile.
3.3. Litsentsisaaja kohustub oma toodetes või teenustes viite andmete päritolule eemaldama litsentsiandja kirjalikul nõudmisel.
I think it’s always better to ask for a permission if you need this data, like it was done with Maa-amet when they didn’t bother with licenses.
Chiming in…
The detailed Tallinn maps are, like, really detailed. Grassy areas galore, and one could map trees easily. If only we had a clear idea on the license and also the technical side of using it…
The map tileserver (as is Maa-Amet’s LIDAR data I think?) provides only tiles in EPSG3301 projection. I’ve been trying to investigate what modifications would be needed in iD to support that. So far, I’m seeing that:
- requests for map tiles would have to be made in EPSG3301 coordinates, i.e. translate the WGS84 coords iD (and OSM) uses to EPSG3301 (the Estonian variant of Lambert conformal conical projection)
- reproject the given tiles to WGS84 tiles (i.e. re-distort/re-squish the given tiles to accurately re-map the images to existing OSM map features)
The first part seems (I think) to be doable, in the sense that converting co-ordinates would be a one-time implementation affair, even though I’m not familiar with all this map projection stuff. But even trial and error until a good result is kinda doable I’d say 
The second part is more tricky I think. Getting the tiles to accurately map to OSM data is not guaranteed, and could be impossible, my gut-feeling would say. But I might be wrong and this could also work.
But overall, as qqqqqqqqqqqqqqqqqqqq says, the first question that would need an answer is the licence and/or explicit permission for use on our side.
iD already has support for EPSG4326: iD/background_source.js at develop · openstreetmap/iD · GitHub
But EPSG4326/GPS coordinates are easily back and forth convertible with Mercator lat/long.