[OSM-talk-ie] When is a townland a townland (and when is it 2+ townlands)?

[Rory McCann]

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Hi all,

Thanks for the replies, it looks like there are many good reasons for
things to be mapped this way. I won't change anything.

I'll tweak the logainm import script to not throw an error in these case
s.

Rory

On 29/05/16 11:39, Rory McCann wrote:
> Hi all,
> 
> A while ago I mentioned a possible problem with the Logainm data 
> import, where 2+ townlands were getting the same logainm
> reference[1]. Upon closer investigation, I don't think this is a
> bug with the import process, but a question of "Is a townland is
> one townland or many townlands?".
> 
> Consider Graiguealug townland in Carlow. It's in OSM as 3
> different townlands: OSM ids
> https://www.openstreetmap.org/relation/2196774 
> https://www.openstreetmap.org/relation/2274862 
> https://www.openstreetmap.org/relation/2274863 all touching each 
> other. Each is in a different civil parish[2].
> 
> However Logainm only has one entry http://www.logainm.ie/en/3531
> which is in 3 different civil parishes. Logainm allows one townland
> to be in more than one CP. If you look at the GSGS map, only one
> townland is shown on the map, and the total area (~400 acres) is
> similar to the total off the 3 townlands in OSM.
> 
> It looks like one townlands was split into 3 townlands so that
> each townland would be in one and only one CP.
> 
> However I don't think this is the right approach. I think the OSM 
> philosophy of "One Feature, One OSM Element"[3] should apply, and
> that those 3 townlands should be merged into 1. The CP boundaries
> should physically stay where they are, but they will not line up
> with a townland boundary. I seen other examples of townlands
> crossing CP boundaries and have mapped them as one townland, with a
> CP border going through the middle.
> 
> I'm tempted to merge townlands like this into one townland. What
> do people think?
> 
> Rory
> 
> [1] 
> https://lists.openstreetmap.org/pipermail/talk-ie/2016-March/001499.ht
ml
>
> 
[2] Townlands.ie:
> https://www.townlands.ie/carlow/forth/templepeter/templepeter/graiguea
lug/
>
> 
https://www.townlands.ie/carlow/forth/tullowmagimma/templepeter/graiguea
lug/
> https://www.townlands.ie/carlow/forth/nurney/templepeter/graiguealug/
>
> 
[3] https://wiki.openstreetmap.org/wiki/One_feature,_one_OSM_element
> 
> _______________________________________________ Talk-ie mailing
> list Talk-ie at openstreetmap.org 
> https://lists.openstreetmap.org/listinfo/talk-ie
> 
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