Changeset: 45201297
Survey, checked location with Garmin
Closed by Peter Fowler
Tags
created_by | iD 2.0.2 |
---|---|
host | https://www.openstreetmap.org/id |
imagery_used | Bing aerial imagery |
locale | en-US |
Discussion
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Comment from BCNorwich
The number suggests a triangulation pillar then type=triangulation can be added. Please see here :- https://wiki.openstreetmap.org/wiki/Tag:man_made%3Dsurvey_point
Regards -
Comment from Peter Fowler
Sure.
I am very, very new here, and I read the paragraph,
> type=triangulation,
> type=observation_spot,
> type=fixed_point and type=benchmark
> have meaning in nautical maps, where
> they refer to INT-1 codes B20, B21, B22
> and B23 respectively. Note: it would be
> better to use a different key when
> tagging these values, for example
> survey_point=triangulation or
> survey_point:type=triangulation. See
> Key:type for more info about why
> type=* is to be avoided outside of
> relations.as counseling against adding =triangulation unless in the context of a nautical map. Further, had I decided to add such a tag, I would have been guided by the comment about type= (and I may have got that wrong, actually, as there seems to be a type= and a survey_point:type=triangulation).
There is very little material about triangulation pillars in the forum or the wiki, which struck me as odd, as checking the ability to identify and/or mark known fixed points on the map seems to be an obvious thing to do when starting out. It must look as though I was practising for the practical of an Englishness test.
Is there a way of looking at every node with a tpuk_ref= tag so I can see what others have done?
(Note: The Garmin recorded the elevation, of the top plane of the pillar, as 149 (units?); and the Ordnance Survey give the HEIGHT as 150.330, presumably metres above Newlyn. I didn't add either, because I see reason to trust my measurement, even if I knew t=what it was, and there might a copyright problem with copying the Ordnance Survey's datum).
I am very grateful for your attention, and most grateful for your help.
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Comment from SomeoneElse
"type=triangulation" was a new one to me too...
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Comment from SK53
type=* anything should be avoided as type really should be reserved for relations. I would agree with either of survey_point or survey_point:type as being suitable values.
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Comment from Peter Fowler
Please believe me that I had no notion how difficult I would find this. Please feel invited to fill in the correct tags perhaps from http://trigpointing.uk/trig/3033 . Further, I am not quite certain that the [wiki page that I used](https://wiki.openstreetmap.org/wiki/Tag:man_made%3Dsurvey_point) is well laid out and comprehensible.
At some point I will go and take a look at [Wood Close](http://trigpointing.uk/trig/7029) and [Launde](http://trigpointing.uk/trig/4367) .
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Comment from Peter Fowler
I have found, on my shelves, a paper copy of sheet 122 of the Seventh Series (Melton Mowbray) published 1962. Looking at SK865065, it is between the 500 foot and 450 foot contour line, I would judge at about 470 feet, maybe a little higher. Should I add this figure, or the one from the Garmin (149 metres)? (Or neither?).
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Comment from SK53
Not to worry: somewhat surprisingly trig pillars are not that well documented. This discussion is useful for helping clarify what should be documented. By a remarkable co-incidence last weekend I also mapped a trig pillar featured on sheet 122 (http://www.openstreetmap.org/node/4608321916), so it's helping me too.
My copy of the map has your point with a spot point of 492 ft which is just shy of 150 m. I'd run with either 149 or 150.
Normally for lowland Britain I just transform old OS heights to metres before adding to OSM. You can also add ele:ft=492 but this ain't really necessary.
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Comment from Peter Fowler
OK. My map does not appear to have the spot height. The green Pathfinder 896 has metric contours and a spot height of 150 and the Orange Explorer 15 is identical. My only concern is to avoid being accused of wrongful copying of the issued data from [TrigpointingUK](http://trigpointing.uk/trig/3033) .
P.S. I might not get to it for a month or so, but I have waypoints for three Posting Boxes near Stamford Road, and six Benchmarks, and a track for some new development off the Uppingham Road. If someone wants to to pip me to the post …
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Comment from SK53
My map is issue B/* (c) 1962, updated with PRoW and major roads 1967. I notice the map on NLS doesnt have the spot height either, and the earlier interpolated contours on the 6" and 2.5 inch OOC maps dont really agree with the spot height (http://maps.nls.uk/geo/explore/#zoom=17&lat=52.6502&lon=-0.7246&layers=10&b=2). I guess the ground rises more steeply from the Uppingham Road.
I'm probably not going to in Rutland until August so I suspect you'll still get the chance.
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Comment from Peter Fowler
Thank you.
I have never previously seen that map, and I agree that the land rises quite steeply from the Uppingham Road. This triangulation pillar does not seem to be shown. Had it been erected? The OS claim that their "leveling" dates from 1963. Perhaps the contour lines on the 1937-61 maps are not correct!
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