Bing imagery source on higher zoom levels inconsistent with iD

[planemad]

This is just a technical question, not a bug report.

While reviewing some building edits, noticed a significant difference in quality of imagery in JOSM and iD at the same zoom level and location.

For this location in India, JOSM switched to higher res Bing imagery at z19 while iD does not. When I filed a ticket describing this at the iD repo, it was mentioned that the imagery source is not Bing. Details: ​https://github.com/openstreetmap/iD/issues/2640#issuecomment-101296918

The reply was:

Yeah JOSM is definitely switching imagery beyond z19.. I don't know what they are doing, but I'm pretty sure that imagery is not coming from Bing.
I did try requesting tiles from Bing for this area, but they are not returning anything for z19, so iD overzooms.
For example, this request returns a 200 response but X-VE-Tile-Info: no-tile.

Can someone shed more information on the imagery source and request url at these zoom levels, that I could use it in the iD ticket?

[Klumbumbus]

the sources for imageries are here: Maps

[bastiK]

I don't get this magic high resolution. Same as iD in the screenshot for me.

Could be old imagery from the cache, as the spot is at the border of high resolution and not-so-high resolution.

[Klumbumbus]

I can see the high res imagery in JOSM, and I don't think that I visited this area before with JOSM, so it can not be in my cache.

[planemad]

The condition of roads in the JOSM imagery is significantly better and looks newer than whats showing up in iD

[bastiK]

Here is a tile I see in JOSM:

It is identical to the iD screenshot.
The tile URL is ​http://ecn.t1.tiles.virtualearth.net/tiles/a123310233313321321.jpeg?g=3485

[wiktorn]

Replying to Klumbumbus:

I can see the high res imagery in JOSM, and I don't think that I visited this area before with JOSM, so it can not be in my cache.

I just visited this place with JOSM and I haven't seen high res imagery. To be sure that it doesn't comes from cache, please flush the tile cache, before checking this place.

The only thing, that might be the case, is that cache keys are based on tile numbers and name of the source. If there are two sources with the same name, but different source, they might get mixed up. I consider changing the cache key to templated url + tile numbers to avoid such possibility.

[bastiK]

Replying to wiktorn:

The only thing, that might be the case, is that cache keys are based on tile numbers and name of the source. If there are two sources with the same name, but different source, they might get mixed up. I consider changing the cache key to templated url + tile numbers to avoid such possibility.

AFAIK it is based on tile number and id. The id is guaranteed to be unique. Only problem might be for custom entries that don't have an id. Maybe we should assign a random one for these.

[planemad]

Can confirm i'm seeing the high res imagery even after flushing tile cache.

Infact I can see three different image scenes while zooming in/out.

Screencast: ​https://cloud.githubusercontent.com/assets/126868/7607348/2a923410-f97e-11e4-8601-8127d20167df.gif

[bastiK]

Replying to planemad:

Can confirm i'm seeing the high res imagery even after flushing tile cache.

Infact I can see three different image scenes while zooming in/out.

Screencast: ​https://cloud.githubusercontent.com/assets/126868/7607348/2a923410-f97e-11e4-8601-8127d20167df.gif

This looks different for me: It zooms in up to level 19, the imagery looks consistent at least in the range of 16-19. No tiles at 20.

In contrast, you seem to have 3 different imagery versions, depending on zoom level. (location is 16.817041353797542, 81.52973439240682 by the way)

Could you give a tile URL for one of the high-resolution tiles? (You can start JOSM with --debug command line option or use tools like wireshark.)

[wiktorn]

Closing as no answer from reporter