Greetings! Indeed, in general the Bing satellite image layer may have an offset relative to the ground, yet, in this case (Fremont, CA) when opening both layers (Microsoft and Fremont municipal layer) in JOSM, I can see that the Microsoft layer is aligned fine with Bing imagery (which, in turn, is aligned fine with available GPS tracks), while the municipal layer is slightly shifted – and the shift is different for different blocks. Recently, when I drew buildings in Berkeley, CA, and encountered the same issue – the municipal layer has a slight offset, while the MS layer on average is well aligned.
To the question on why the municipal layers may have bigger offsets than the MS footprint layer: e.g., for Berkeley, CA, I know that their building footprint layer was created in the first place for estimating the solar potential of the roofs in the city, so, I guess, the accurate geometry of buildings was important for that task, while the precise location of buildings less so. Thus, the municipal layer has precise geometries but not very precise locations. But, again, this is just my guess. Yes, squaring helps remove some excessive details. Best, Yury On Tue, Oct 20, 2020 at 7:08 AM <[email protected]> wrote: > Send Imports-us mailing list submissions to > [email protected] > > To subscribe or unsubscribe via the World Wide Web, visit > https://lists.openstreetmap.org/listinfo/imports-us > or, via email, send a message with subject or body 'help' to > [email protected] > > You can reach the person managing the list at > [email protected] > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of Imports-us digest..." > > > Today's Topics: > > 1. Re: Buildings in Fremont, CA ([email protected]) > 2. Re: Buildings in Fremont, CA (Frederik Ramm) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Mon, 19 Oct 2020 08:16:29 -0400 > From: [email protected] > To: [email protected] > Subject: Re: [Imports-us] Buildings in Fremont, CA > Message-ID: > <[email protected]> > Content-Type: text/plain; charset="UTF-8" > > Hello, > > I have some questions about the MS-buildings footprints. As I > understand it, the Bing aerial imagery has an offset from the ground > truth, and thus the MS-buildings footprints that derive from it. I see > you have corrected the offset for the Fremont building footprints, but > aren't they still offset? Do they now line up with the ground truth? > > I ask these questions because I also plan on importing building > footprint data myself. > > On Sun, 2020-10-18 at 23:47 -0400, Yury Yatsynovich wrote: > > Greetings! > > As a continuation of my effort to import addresses in Alameda County, > > California, I've been working on importing buildings for Fremont, CA. > > Please, find a wiki page with a detailed description of this import > > here: > > https://wiki.openstreetmap.org/wiki/Fremont_CA_Buildings_Import. > > Any feedback would be much appreciated. > > Best, > > -- > > Yury Yatsynovich > > _______________________________________________ > > Imports-us mailing list > > [email protected] > > https://lists.openstreetmap.org/listinfo/imports-us > > > > > > ------------------------------ > > Message: 2 > Date: Mon, 19 Oct 2020 14:33:11 +0200 > From: Frederik Ramm <[email protected]> > To: [email protected] > Subject: Re: [Imports-us] Buildings in Fremont, CA > Message-ID: <[email protected]> > Content-Type: text/plain; charset=utf-8 > > Hi, > > On 10/19/20 05:47, Yury Yatsynovich wrote: > > https://wiki.openstreetmap.org/wiki/Fremont_CA_Buildings_Import > > I am curious why the county GIS department apparently has data that is > so low-quality that Microsoft's consumer-grade data can be used it > improve its positional accuracy? > > The web site mentions the squaring of buildings. Is this to get rid of > unwanted detail like the litte nooks visible in the 7 o'clock house in > your image here > https://wiki.openstreetmap.org/wiki/File:Fremont_after_offset.png? > Becasue I would agree that the building outlines in that image are > seriously over-detailed for OSM. > > Bye > Frederik > > -- > Frederik Ramm ## eMail [email protected] ## N49°00'09" E008°23'33" > > > > ------------------------------ > > Subject: Digest Footer > > _______________________________________________ > Imports-us mailing list > [email protected] > https://lists.openstreetmap.org/listinfo/imports-us > > > ------------------------------ > > End of Imports-us Digest, Vol 73, Issue 3 > ***************************************** > -- Yury Yatsynovich
_______________________________________________ Imports-us mailing list [email protected] https://lists.openstreetmap.org/listinfo/imports-us
