[Tagging] Another multipolygon question

Dave Swarthout daveswarthout at gmail.com
Tue Oct 23 10:22:19 UTC 2018


Many thanks to you. The video was well done and quite interesting. I
started using the techniques you described immediately and it has made my
life incredibly easier. I had just completed the addition of a huge wood
multipolygon to Shuyak Island using my old method yesterday. Then today I
created many multipolygons on a portion of Kodiak National Wildlife Refuge,
Ban Island, using them for woods, wetlands, and then joining 19 sections of
coastline, lagoon, and wood to make the refuge boundary. Awesome. The
Relation Toolbox makes constructing a complex multipolygon from scratch a
snap. Some of the ways I created are shared by 3 or more relations.

Highly recommended for anyone using relations in any form!

Take a look at my first effort with your coaching:
Relation: Ban Island (4253551)
Relation: Kodiak National Wildlife Refuge (8841597)


On Mon, Oct 22, 2018 at 11:35 PM Adam Franco <adamfranco at gmail.com> wrote:

> Hi Dave, all,
> Based on this discussion I just recorded this short tutorial
> <https://youtu.be/x7SPb0JtheA> of how I use JOSM and its Relation Toolbox
> plugin to to add adjoining land-cover areas as multipolygons with shared
> boundary ways to reduce duplication and overlapping ways.
> The area I'm editing, is replete with examples of this type of mapping:
> https://www.openstreetmap.org/#map=14/44.0199/-73.1530
> The tools used are:
> * JOSM editor - https://josm.openstreetmap.de/
> * "Relation Toolbox" JOSM plugin -
> https://wiki.openstreetmap.org/wiki/JOSM/Plugins/Relation_Toolbox
> Documentation on MultiPolygons in the OSM wiki:
> * https://wiki.openstreetmap.org/wiki/Multipolygon_Examples
> * https://wiki.openstreetmap.org/wiki/Relation:multipolygon
> For some reason I've gotten hooked on mapping landcover in my area and
> spend a lot of time adding multipolygons to do so. I find them vastly
> easier to manage, update, and fix than simple closed ways with overlapping
> edges (how I started). As I show in the video, adding detail usually just
> means splitting exiting ways and adding/subtracting using the Relation
> Toolbox.
> Hope this helps someone -- let me know if there are particular cases or
> questions and I'd be happy to record another video covering other
> situations.
> Best,
> Adam
> On Mon, Oct 22, 2018 at 8:47 AM Paul Allen <pla16021 at gmail.com> wrote:
>> On Mon, Oct 22, 2018 at 5:27 AM Dave Swarthout <daveswarthout at gmail.com>
>> wrote:
>>> Great. But what are you actually doing when you "sort the members" of a
>>> relation? And after sorting, how does one "ensure the members are
>>> connected"?
>> Sorting something like a bus route ensures that the various ways that
>> constitute it are connected
>> nose-to-tail.  This is what "ensures the members are connected" and
>> ensures they are connected
>> in a sensible fashion.  Sorta.  It may not do a good job if the route
>> traverses the same way in the
>> same direction more than once.
>> I've noted with dismay the lack of debugging support for relations. For
>>> example, I will get an error message when trying to upload an edited
>>> relation but when I ask JOSM to Zoom to the error, the display zooms out
>>> enough to include the entire relation with no clue as the where the actual
>>> problem is. Same thing when you ask to "jump to the next gap". Good luck on
>>> that also. Maybe it's just me?
>> Nope, it's not just you.  I too have problems getting my head around
>> JOSM.  I use it when I have to,
>> to merge or split areas (such as when I find out that a large forest that
>> somebody else mapped
>> has two named chunks).  It's probable I find it hard to use because I
>> don't use it enough, which means
>> I don't use it much, which means...  But I also have to admit that I find
>> Java programs in general are
>> not a good fit with how my mind expects things to work and they all give
>> me a steeper learning curve
>> than non-Java programs.  Which means I try not to use them much, which
>> means...
>> --
>> Paul
>> _______________________________________________
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>> Tagging at openstreetmap.org
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Dave Swarthout
Homer, Alaska
Chiang Mai, Thailand
Travel Blog at http://dswarthout.blogspot.com
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