The Great University at Buffalo (New York) Realignment

Hey all, just making a quick post to document a change I’m making on the State University of New York at Buffalo North Campus (Way: ‪University at Buffalo - North Campus‬ (‪108635668‬) | OpenStreetMap) (will probably need this on South Campus too, but haven’t gotten there yet).

I’ve taken it upon myself to do some micromapping and otherwise add/improve details around campus, but I’ve had a problem: everything on campus seems to be aligned to different imagery.

Bing, Esri, Mapbox, and New York State-provided imagery are all off a little bit from each other. It’s not enough to be a big deal on a large scale between areas, but far enough that it gets in the way of such level of mircomapping.

For example, taking a look at the north side of Capen Hall:

before_capen

  • The north side of the pedestrian area is aligned to Esri
  • The south side of the pedestrian area is aligned to Bing
  • The footways are mostly aligned to Bing
  • The crosswalks are aligned to Mapbox/NYS Ortho
  • The road is aligned to Bing
  • Capen Hall isn’t perfect with anything, but closest to NYS Ortho

Overall across campus, Bing seems to be the most popular choice. But as you can see, it’s far from the only one, and if I’m bulk-realigning everything already, I’d rather go to the most correct option rather than the most popular.

Ok, so next question: which one is the most correct? GPS traces aren’t precise enough at this scale to be helpful, so I turned to survey markers. After a little searching through the National Geodetic Survey (public domain), I found 3 markers at the Buffalo Niagara International Airport that were clear enough across aerial imagery to be usable for alignment:

N looked to be the most visible overall, so I used that for primary alignment and used the other two as an extra check.

Looking back at the same area after creating offsets:

ezgif-2-cf184666c7

Well, now pretty much everything is misaligned (except for the crosswalks), but at least now it’s all misaligned equally and I have a definitive target to work towards/with. And, everything originally aligned to the same imagery should (theoretically) be off by the same amount, so it should be too terrible, but there some 2,000 ways and 25,000 nodes on campus, sooo… :upside_down_face:

For other mappers, I’ve uploaded the offsets to the Imagery Offset Database from JOSM. Of the default offsets, you can see the state orthoimagery layer is the closest to accurate, with Mapbox very close behind.

For editors without the Offset Database (aka iD), the exact offsets I’ve set are as follows (horizontal E+; vertical N+):

  • Bing
    • 0.81; -1.44
  • Esri
    • 2.22; -2.41
  • Mapbox
    • 0.30; -0.55
  • NYS Ortho
    • -0.32; 0.19

I’m also posting this in the OSM US #local-newyorkstate channel and messaging other mappers I’ve seen around UB North for awareness. I’m not in the Discord, but if there’s a relevant channel there, I don’t mind if someone posts there too. I’ll give things a week, then barring any panicked screams (or polite criticisms), start realigning geometry.

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