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

[Patrick Matthews]

Corravila is represented as two separate entities in Logainm (
http://www.logainm.ie/en/3801 and http://www.logainm.ie/en/130953).

On Sun, May 29, 2016 at 1:04 PM, Patrick Matthews <mullinalaghta at gmail.com>
wrote:

> Corravilla: http://www.openstreetmap.org/relation/5705909
>
> On Sun, May 29, 2016 at 12:50 PM, Patrick Matthews <
> mullinalaghta at gmail.com> wrote:
>
>> Rory, Dave,
>>
>> My inclination is the opposite - there are plenty of situations where you
>> have townlands "split" between civil parishes in exactly the same way as
>> the ones you mention but where one "part" being in one ED and another in a
>> different ED means that the two are shown as separate on the post-1898
>> maps. (There can also be false positives where two completely different
>> townlands in different parishes but with the same name happen to be in the
>> same ED, e.g. Corravilla in east Cavan, where two townlands, one in
>> Shercock parish and one in Knockbride, happen to be in the same ED and are
>> represented in the maps as a single townland, but have different postal
>> addresses and are listed separately in the electoral register.)
>>
>> The methodology of the original Ordnance Survey, for what it's worth, was
>> to treat each "part" of the townland as a separate entity, and they're
>> still recorded as separate entities in the 1901 and 1911 census reports.
>>
>> Baronies split by counties (e.g. Fore, Rathdown) should be treated
>> separately as they were/are county subdivisions. Civil parishes and
>> baronies were always independent of each other so the split doesn't matter
>> there.
>>
>> Regards,
>>
>> Paddy.
>>
>>
>> On Sun, May 29, 2016 at 11:46 AM, Dave Corley <davecorley at gmail.com>
>> wrote:
>>
>>> I have a vague recollection of this being discussed way back. The issue
>>> is
>>> not just with townlands if I recall correctly.
>>>
>>> I think there may also be cp's split by baronies and baronies split by
>>> counties and so on.
>>>
>>> Your logic seems sound to me, but then again I never got to doing cp's.
>>>
>>> Dave
>>> On 29 May 2016 10:40, "Rory McCann" <rory at technomancy.org> wrote:
>>>
>>> > -----BEGIN PGP SIGNED MESSAGE-----
>>> > Hash: SHA1
>>> >
>>> > 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.html
>>> > [2] Townlands.ie:
>>> >
>>> https://www.townlands.ie/carlow/forth/templepeter/templepeter/graiguealug/
>>> >
>>> >
>>> https://www.townlands.ie/carlow/forth/tullowmagimma/templepeter/graiguealug/
>>> > https://www.townlands.ie/carlow/forth/nurney/templepeter/graiguealug/
>>> > [3] https://wiki.openstreetmap.org/wiki/One_feature,_one_OSM_element
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