Changeset: 55918759
General Clean up adjusting roadways and buildings
Closed by Scoop268
Tags
changesets_count | 16 |
---|---|
created_by | iD 2.6.0 |
host | https://www.openstreetmap.org/edit |
ideditor:walkthrough_completed | yes |
ideditor:walkthrough_progress | welcome;navigation;point;area;line;building;startEditing |
ideditor:walkthrough_started | yes |
imagery_used | Bing aerial imagery |
locale | en-US |
source | local knowledge |
Discussion
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Comment from freebeer
Hi Scoop,
The changeset description you gave here had me worried, and looking at your work, which must have taken some time, the worst I feared was true.
You are working in an area which is not well served by detailed aerial imagery, and by default you have used Bing, which is a satellite imagery provided by DigitalGlobe and known to have a signifigant offset in many areas.
I measured that the one building you shifted which I tested now has an offset of four metres from the position the old aerial imagery offered, which in this case is much closer to reality.
The older imagery, which includes some buildings you deleted, is available either as Mapbox, or now officially as ESRI (Clarity) Beta.
The third source is the USGS Large Scale imagery, which is poor in detail but well-aligned everwhere I have tested so that it is a reasonable reference.
Do you know about these alternate imagery layers, available to you with the kezboard command `b' ?
.
I have made comments to other changesets about this, but I have not yet made a template, nor noted the URLs to allow you to read what I wrote there.
If you want to work with Bing as the newest, you are also able to shift that to match the positioning of the other images.
I don't know if you want your work to be undone, but it is possible, if you agree things are now misplaced, and don't want to move things again. You would lose, as far as I see, only a few deleted buildings.
I hope this makes sense....
Thanks! -
Comment from Scoop268
I see exactly what you mean... I had no idea that you could adjust the background map to align it to the overlay... I used your background imagery and see what you mean.... I would say that if you could just undo the work that I have done that would be the best.
Now that I know about the imagery alignment issue, I would rather just start over....
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Comment from Scoop268
If you can delete the change sets that I have done today that would be fine.
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Comment from freebeer
Hi again...
Sorry, I sent off that comment shortly before falling asleep, and before I saw you had done several more, more complex changesets, earlier that day.
I'm writing this shortly after awakening, and once in a Blue Moon I like to go outside, so if it's okay, I'll return to this after I dust the cobwebs into the corners of me brane, in a few hours.
If someone else wants to join in and do this, feel welcome. There look to be from the changeset descriptions up to ten that may be candidates (I only ran the newest three or four through achavi for a diff overview:
https://resultmaps.neis-one.org/osm-suspicious?uid=609462#11/47.3914/-97.0529
)
Also, it may be possible to recover any additions you have drawn from scratch - but in the ``wrong'' places; I will look into this when I sprawl out on the floor later. -
Comment from Scoop268
So I just took a quick peak at the map edits that I had done yesterday, with changing the background imagery... Now that I am awake again, I took a closer look.
(Hopefully you had a good view of the blue blood moon where you were)
Bing, DigiGlobe, ESRI all had the same issue... they were all about 4 meters to the west before you adjust the background map... appearing to be very close to the same issues that I thought I was adjusting last night with the bing imagery. When I pull up USGS the background imagery is maybe 2 meters to the west, but also about 1 meter to the south... (These three appeared to be about the same)
The only map that was spot on was the Mapbox map... and since this is the only Map that appears to be "accurate" to the background imagery, I feel confident in saying that whoever did these edits was using that imagery.
So the big question is... which background map is actually an accurate depiction of what I need to work on? Or are they all just a little off? I now see why the background imagery can be adjusted! It had been several years since I had worked with open street and I took the tutorial again just to brush up, and I wish it would have covered this important issue.
So moving forward... What imagery is really accurate? I will then use that to begin work and once I have a point of reference, I should be able to work with bing after the adjustment is made to correct any error. I just need to know if the Mapbox was accurate when it was first completed...
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Comment from freebeer
Hi,
Sorry for not replying sooner. After spending time in the fresh air, I somehow was motivated to recover from my sleep deprivation. And I think it worked, so four days later...
There are changes happening in other parts of the US to the Mapbox/DigitalGlobe Premium layers within the past weeks or days, so at least around major cities, I'd have to review the imageries before everything I write.
That said, if the Mapbox imagery only allows you up to native zoomlevel 19, and is visually identical to ESRI Clarity, and the rest are awful blurs with obvious perspective issues, stick with the former.
.
There are areas where there had been, until a couple years ago, much sharper and better imagery from USGS. In one area I mapped, probably West Virginia or nearby, there was maybe a metre or two difference, and as you could get two crisp zoomlevels further in to see details on sheds and such, plus those details were aligned to buildings I'd traced earlier but someone adjusted, there are probably allowable government references in detail, maps that are accurate and better than the USGS Topo maps, but which aren't listed as imageries.
As the original Bing imageries were replaced by z20 images with a high level of correction, that became my reference. You don't see it here, but where I can compare, it aligns well.
Now in other parts of the country, there is, say Texas Orthophoto also at z20 which may not quite align in detailed editing, and ESRI/Mapbox seem to have z21 and even z22 imageries in some areas.
These I sort of have to, by default, assume are aligned and corrected well to meet the standards of the sponsoring agency. We are talking of pixels with 5cm resolution or so, versus the coarseness of maybe ten years ago or actual satellite photos of today.
I'm sure there are better descriptions and tutorials about this; I last skimmed a german wiki page about aerial imageries and offset not long ago.
If you have a known-good map reference, as are available for parts of germany, that can be used for precise alignment.
The better the imageries become, the more uncorrected mapping/perspective errors come into play, like tracing the roof but failing to slide it to match the ground level at which the image was aligned to a particular elevation model.
The general rule I see is, align to what exists. Of course, if someone starts and adds things from 4-metre-off aerials with hills and all, that's sub-optimal, but those images are pretty rubbish to start with.
Until you get better imagery here, the oldest but clearest is probably best for alignment. Once you can fill in the hairpieces of pedestrians, then you can worry about correcting things that don't quite meet up, and perhaps reference known-position markers will be visible.
Short answer? It Depends. For now, Mapbox. It's known old; you can update it from the newer Bing/DG/ESRI.
.
That off-topic rambling unintelligible drivel out of the way, I want to apologise for not attending to the reverts sooner, and ask, should I start?
If you have changed anything since, like moved a road or building in the past two days, I think it'll be left alone from your newer changes.
If you've not moved the majority of things, I think most buildings should pop back into place.
That said, I'll start, since you seem to wish this, and I'll attempt to summarise what works and what fails (I've so far only done successful reverts with untouched items, so not witnessed things crashing and burning, yet).
I'll try to do a slow-but-good job with this... -
Comment from freebeer
This one ... is .... well, eyeballing it, some six or so small buildings/sheds will be re-animated. Not too bad.
Nodes: 110 2810 76 Ways: 20 5 16 Relations: 000
The exact details on what 16 ways you deleted are listed directly below on this page, along with whatever random nodes will come back to life.
This works near the government buildings you moved, but does not touch them.
Will as usual start a dry-run first. -
Comment from freebeer
Details of the 20 new ways that you added, including three car parks, are listed on page 2 below of Ways with one straggler on page three.
I can make out some of them in the achavi URL, including a rounded tank-or-something near one you shifted. (The washed-out-yellow is too close to the washed-out-green here with two of my on-screen clocks in those rich colours somewhat better.)
.
These deleted objects can in theory be restored to life with some Flash editor magic, if things are not too messy and if you think it is worth the bother.
.
I am not sure if I have the patience for this whole dry-run, so here we go -
Comment from freebeer
This changeset has been reverted fully or in part by changeset 56067398 where the changeset comment is: Undo misguided alignment to newer satellite rather than aerials
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