[Talk-us] Adding a new node by merging borders of two other existing nodes?

[Minh Nguyen]

Vào lúc 05:32 2022-03-18, Reem Ali Suwaileh đã viết:
> The name "Carolinas" is commonly used to describe both North Carolina 
> and South Carolina. These states exist separately on OSM. I wanted to 
> add a new node for "Carolinas" as it's commonly used on social media 
> this way but wants to hear from you first?
> 
> I want an easy way to create a node by merging existing North Carolina 
> and South Carolina borders. Is this possible? I need that because I work 
> on automating the extracting of locations names over social media posts 
> and wants to link those locations against OSM.

Can you elaborate on what you'd like to do with the geotagged social 
media posts? Do you intend to plot them on a map or return relevant 
posts when a user searches for a place name?

There is precedent for adding a place=region node at a very rough 
centerpoint within the region. [1] However, this representation doesn't 
communicate anything about the extent and shape of the region. Since 
you've mentioned borders, do you also need the "borders" of the 
Carolinas, not just a point location?

Presumably you'd be interested in the names of many informal regions, 
not just "the Carolinas". The Carolinas happen to be well defined (as a 
pair of states proper) and have as much a historical basis as New 
England [2], but many other regions are less well defined or subject to 
interpretation. Of course the same is true of neighborhood names as 
well. This is a topic that's relatively underdeveloped within 
OpenStreetMap, in part because of concerns about subjectivity.

You wouldn't merge the boundaries of two states under any circumstance; 
that would be stating that North and South Carolina no longer exist as 
distinct states. However, OSM does have a few scattered examples of 
regions and neighborhoods with well-defined, uncontested boundaries:

* Contiguous United States
   type=boundary boundary=region place=region
   https://www.openstreetmap.org/relation/9331155

* New England
   type=multipolygon place=region
   https://www.openstreetmap.org/relation/9660059

* Fairview, CUF, Cincinnati
   type=boundary place=suburb
   https://www.openstreetmap.org/relation/2961228

* Fruit Belt, Buffalo
   type=boundary boundary=neighbourhood place=neighbourhood
   https://www.openstreetmap.org/relation/9418827

By contrast, here's an example of a region that's poorly and 
subjectively defined. After some back and forth [3], we settled on 
mapping it as a node at a location that's historically significant to 
the region:

* Silicon Valley
   place=region
   https://www.openstreetmap.org/node/5368437129

These examples may serve as models to follow if you go ahead with 
mapping the Carolinas as a region. However, you may want to step back 
and consider whether OSM's objective approach to mapping clear-cut 
places will be adequate for your use case. Here are some alternatives 
that you may find more immediately useful as a source for your project, 
even if the Carolinas turn out to be mappable per se:

* The Pelias geocoder [4] supplements OSM's boundary data with 
Quattroshapes. [5] Quattroshapes itself aggregates less formal region 
and neighborhood names by, for example, clustering Foursquare checkins 
and Flickr geotagged photos.

* Wikidata has items about many informal regions [6], and you can always 
add one as long as it's described in a reputable source or database. It 
allows for multiple "coordinate location" properties or multiple 
"geoshape" properties annotated with sources. That project's community 
forum may be able to help you get the data you need from the Wikidata 
API. [7]

Hopefully the other impassioned responses to your question haven't 
completely turned you off from OSM. There's a lot of sensitivity around 
borders, just like in real life, but the examples above show that your 
line of thinking wasn't totally off the mark.

Good luck with your project!

[1] https://wiki.openstreetmap.org/wiki/Tag:place%3Dregion
[2] https://en.wikipedia.org/wiki/Carolinas
[3] 
https://lists.openstreetmap.org/pipermail/talk-us-sfbay/2018-January/000007.html
[4] https://pelias.io/
[5] http://quattroshapes.com/
[6] https://www.wikidata.org/wiki/Q2747220
[7] https://www.wikidata.org/wiki/Wikidata:Project_chat

-- 
minh at nguyen.cincinnati.oh.us