#19482 closed defect (othersoftware)
JOSM adds blur to aerial imagery? — at Version 6
| Reported by: | dieterdreist | Owned by: | team |
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| Priority: | normal | Milestone: | |
| Component: | Core | Version: | |
| Keywords: | imagery, mapbox, blur | Cc: |
Description (last modified by )
This is nothing new but something I am experiencing for many years now. JOSM seems to blur the imagery on high zoomlevels. I am not sure it happens with every source (e.g. Bing does not seem so, but then they are blurry around here anyway, so I am not sure).
It seems to happen with mapbox imagery. Please look at the attached screenshots which show the unblurred and blurred layer.
Or maybe it is something that mapbox does upstream?
PS: It may not be completely evident from looking at the screenshots, but if you compare the smaller zoomlevel in 200% viewing size to the higher zoomlevel at 100% (i.e. same real life scale) it becomes very clear the there is some blurring going on, the 200% scaled zoom is much sharper than the 100% 1:1 screenshot.
Change History (9)
comment:1 by , 6 years ago
| Description: | modified (diff) |
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| Summary: | JOSM add blur to aerial imagery → JOSM adds blur to aerial imagery? |
by , 6 years ago
| Attachment: | Screenshot 2020-07-03 at 12.46.59.png added |
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by , 6 years ago
| Attachment: | Screenshot 2020-07-03 at 12.47.10.png added |
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comment:2 by , 6 years ago
| Description: | modified (diff) |
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by , 6 years ago
| Attachment: | Screenshot 2020-07-03 at 12.46.59_comparison.png added |
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comment:3 by , 6 years ago
| Description: | modified (diff) |
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I have now added a third screenshot (comparison) to make it easy to see. The 200% was made without interpolation (no lanczos, cubic or similar).
comment:4 by , 6 years ago
The interpolation comes from mapbox. They deliver tiles on higher zoom levels interpolated from lower zoom levels if no higher zoom levels are available.
The problem is that such global sources as mapbox have different ("true") maximum zoom levels depending on the area.
If you only edit in one area you can adjust the max zoom in the imagery preferences. Then JOSM enlarges the tiles from the max zoom level, resulting in a sharp pixelated display.
General solutions could be:
- mapbox disables interpolation on the higher zoom levels
- mapbox delivers no tiles if no tiles are available at that zoom level
- mapbox delivers "dummy tiles" if no tiles are available at that zoom level (they did in the past) JOSM can detect these and instead display enlarged tiles from lower zoom
comment:5 by , 6 years ago
Thank you for taking the time to respond. I have created a question in the mapbox forum on stackoverflow for this issue:
https://stackoverflow.com/questions/62715967/refrain-from-blurring-aerial-imagery-high-zoom-images
comment:6 by , 6 years ago
| Description: | modified (diff) |
|---|---|
| Resolution: | → othersoftware |
| Status: | new → closed |
Please reopen if someone knows a way to improve this from the JOSM side.
comparison of 100% screenshot with a screenshot of a smaller scale in 200% with no fancy interpolation