[Talk-us-massachusetts] Talk-us-massachusetts Digest, Vol 38, Issue 1

Yury Yatsynovich yury.yatsynovich at gmail.com
Fri Nov 1 12:23:45 UTC 2019 

I was using multipolygons when splitting large buildings into smaller ones
in Boston (e.g. see the area near Fensway), rather than drawing separate
closed ways for each building. But I'm not sure that either way is strictly
preferred -- both seem equally acceptable (I asked this same question in a
Telegram channel "OSM Belarus" and didn't receive any clear answer why one
approach is better than the other, it was all about preferences).

On Fri, Nov 1, 2019, 8:06 AM <
talk-us-massachusetts-request at openstreetmap.org> wrote:

> Send Talk-us-massachusetts mailing list submissions to
>         talk-us-massachusetts at openstreetmap.org
>
> To subscribe or unsubscribe via the World Wide Web, visit
>         https://lists.openstreetmap.org/listinfo/talk-us-massachusetts
> or, via email, send a message with subject or body 'help' to
>         talk-us-massachusetts-request at openstreetmap.org
>
> You can reach the person managing the list at
>         talk-us-massachusetts-owner at openstreetmap.org
>
> When replying, please edit your Subject line so it is more specific
> than "Re: Contents of Talk-us-massachusetts digest..."
>
>
> Today's Topics:
>
>    1. Is there a MA policy on mapping polygons with shared ways?
>       (Wayne Emerson, Jr.)
>    2. Re: Is there a MA policy on mapping polygons with shared
>       ways? (Greg Troxel)
>    3. Re: Is there a MA policy on mapping polygons with shared
>       ways? (Alan & Ruth Bragg)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Thu, 31 Oct 2019 15:45:34 -0400
> From: "Wayne Emerson, Jr." <ibemerson at verizon.net>
> To: Massachusetts List <talk-us-massachusetts at openstreetmap.org>
> Subject: [Talk-us-massachusetts] Is there a MA policy on mapping
>         polygons with shared ways?
> Message-ID: <5eeba1a4-a57f-44d5-8246-69dc692e0d6d at verizon.net>
> Content-Type: text/plain; charset="utf-8"; Format="flowed"
>
> In this weeks OSM weekly roundup http://weeklyosm.eu/archives/12467
> there is this quote, "Adam Franco created two videos about working with
> multipolygons using JOSM. Thefirst one
> <https://www.openstreetmap.org/user/Adam%20Franco/diary/390981>is about
> creating multipolygons for adjoining areas with shared ways. Please note
> that this type of mapping is being discouraged in many parts of the world."
>
> I wasn't sure which type of mapping was being discouraged. So for
> example if we have a swamp bordering a salt marsh, which is bordering a
> tidal flat, should we have 3 polygons with overlapping lines & shared
> nodes, or do we make them into multipolygon relations?
>
> Thanks,
>
> -Wayne / OSM:Rassilon
>
>
>
> --
> This email has been checked for viruses by Avast antivirus software.
> https://www.avast.com/antivirus
> -------------- next part --------------
> An HTML attachment was scrubbed...
> URL: <
> http://lists.openstreetmap.org/pipermail/talk-us-massachusetts/attachments/20191031/1037b096/attachment-0001.html
> >
>
> ------------------------------
>
> Message: 2
> Date: Thu, 31 Oct 2019 16:30:51 -0400
> From: Greg Troxel <gdt at lexort.com>
> To: "Wayne Emerson\, Jr. via Talk-us-massachusetts"
>         <talk-us-massachusetts at openstreetmap.org>
> Subject: Re: [Talk-us-massachusetts] Is there a MA policy on mapping
>         polygons with shared ways?
> Message-ID: <rmid0ecmzd0.fsf at s1.lexort.com>
> Content-Type: text/plain
>
> "Wayne Emerson, Jr. via Talk-us-massachusetts"
> <talk-us-massachusetts at openstreetmap.org> writes:
>
> > In this weeks OSM weekly roundup http://weeklyosm.eu/archives/12467
> > there is this quote, "Adam Franco created two videos about working
> > with multipolygons using JOSM. Thefirst one
> > <https://www.openstreetmap.org/user/Adam%20Franco/diary/390981>is
> > about creating multipolygons for adjoining areas with shared
> > ways. Please note that this type of mapping is being discouraged in
> > many parts of the world."
> >
> > I wasn't sure which type of mapping was being discouraged. So for
> > example if we have a swamp bordering a salt marsh, which is bordering
> > a tidal flat, should we have 3 polygons with overlapping lines &
> > shared nodes, or do we make them into multipolygon relations?
>
> I am not really following.
>
> Sometimes, people use ways that make up a road as landuse boundaries,
> and this seems generally agreed to be bad.
>
> If you mean there are a bunch of ways, and then there are adjacent
> polygons that each contain the boundary way, such that:
>
>   - the boundary way really is the boundary between swamp and marsh
>
>   - the boundary way does not have tags
>
>   - the two polygons have tags
>
> then to me that seems not problematic.
>
> I don't see how you'd use a multipolygon to represent this; that would
> make sense when there were holes, or multiple areas that are logically
> the same.  Even still, I could see a multipolygon of one type using ways
> and another multipolygon also using the ways.  But this doesn't seem to
> change the shared way notion.
>
> When I map landuse, I tend to not share ways, but instead to have ways
> on each parcel group just inside.  But I don't think that's better; it's
> just what I know how to cope with easily in JOSM.
>
> Hope this helps; not really sure at all!
>
>
>
> ------------------------------
>
> Message: 3
> Date: Thu, 31 Oct 2019 18:26:48 -0400
> From: "Alan & Ruth Bragg" <alan.ruth.bragg at gmail.com>
> To: "Wayne Emerson, Jr." <ibemerson at verizon.net>,  OSM Massachusetts
>         <talk-us-massachusetts at openstreetmap.org>
> Subject: Re: [Talk-us-massachusetts] Is there a MA policy on mapping
>         polygons with shared ways?
> Message-ID:
>         <CAJNWF5BcQQuWysZUJpdV+GrMDoaoH1uwg1rJHbsZva1L=
> 7vm-w at mail.gmail.com>
> Content-Type: text/plain; charset="utf-8"
>
> Hi Wayne, Good question. I've tried both methods.
> Simple polygons with overlapping ways are very easy to understand.
> Multiple polygon relations sharing common ways might work better for folks
> who think faster than me but I find them hard to understand.
> Take a look at Mass Audubon in Wellfleet
> https://www.openstreetmap.org/way/29848715#map=15/41.8792/-69.9921 where I
> used multi polygon relations for all types tidal flats, wetlands, woods,
> beaches etc. It gives me a headache just to trying to understand what I
> did.
>
> I think it's better to keep it simple and only use multipolygons when you
> need to put something inside something else.
> Alan
>
>
> On Thu, Oct 31, 2019 at 3:48 PM Wayne Emerson, Jr. via
> Talk-us-massachusetts <talk-us-massachusetts at openstreetmap.org> wrote:
>
> > In this weeks OSM weekly roundup http://weeklyosm.eu/archives/12467
> there
> > is this quote, "Adam Franco created two videos about working with
> > multipolygons using JOSM. The??first one
> > <https://www.openstreetmap.org/user/Adam%20Franco/diary/390981>??is
> about
> > creating multipolygons for adjoining areas with shared ways. Please note
> > that this type of mapping is being discouraged in many parts of the
> world."
> >
> > I wasn't sure which type of mapping was being discouraged. So for example
> > if we have a swamp bordering a salt marsh, which is bordering a tidal
> flat,
> > should we have 3 polygons with overlapping lines & shared nodes, or do we
> > make them into multipolygon relations?
> >
> > Thanks,
> >
> > -Wayne / OSM:Rassilon
> >
> >
> > <
> https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=emailclient&utm_term=icon>
> Virus-free.
> > www.avast.com
> > <
> https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=emailclient&utm_term=link
> >
> >
> <#m_943370204248019100_m_3713208556892737264_DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
> > _______________________________________________
> > Talk-us-massachusetts mailing list
> > Talk-us-massachusetts at openstreetmap.org
> > https://lists.openstreetmap.org/listinfo/talk-us-massachusetts
> >
> -------------- next part --------------
> An HTML attachment was scrubbed...
> URL: <
> http://lists.openstreetmap.org/pipermail/talk-us-massachusetts/attachments/20191031/14e590a7/attachment-0001.html
> >
>
> ------------------------------
>
> Subject: Digest Footer
>
> _______________________________________________
> Talk-us-massachusetts mailing list
> Talk-us-massachusetts at openstreetmap.org
> https://lists.openstreetmap.org/listinfo/talk-us-massachusetts
>
>
> ------------------------------
>
> End of Talk-us-massachusetts Digest, Vol 38, Issue 1
> ****************************************************
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openstreetmap.org/pipermail/talk-us-massachusetts/attachments/20191101/d05dcb85/attachment.html>

More information about the Talk-us-massachusetts mailing list