TrigpointingUK

The TrigpointingUK database contains many triangulation pillars for Ireland. I'm curious to know the provenance of the coordinates for such please, especially within Eire itself.

Were they all originally provided by Tailte Éireann (formerly Ordnance Survey Ireland - OSi), or does this only apply to those with names which have OSI in brackets afterwards? Were these provided in Irish Grid coordinates, or something else please? If others didn't come from OSI what is their provenance and what CRS were the coordinates originally provided in?

Many thanks

Andy

on a similar subject...

This might well be a known issue but there seems to be quite a
number of duplicate records in the trig database, relating to
the import of the Irish trigs. A few examples:

27166 TP27166 Wolftrap Mountain G none none 53.05971 -7.30569 N 436 012
27169 TP27169 Wolftrap Mountain G none none 53.05971 -7.30569 N 436 012

27164 TP27164 Wilkinstown G none none 52.37191 -6.6426 S 925 253
27168 TP27168 Wilkinstown G none none 52.37191 -6.6426 S 925 253

27160 TP27160 White Mountain X none 3rd order 54.54438 -6.08625 J 238 679
27165 TP27165 White Mountain X none 3rd order 54.54438 -6.08625 J 238 679

27152 TP27152 Tullymoy G none none 54.04022 -8.79752 G 478 104
27157 TP27157 Tullymoy G none none 54.04022 -8.79752 G 478 104

27148 TP27148 Tullygerravra G none 3rd order 54.37328 -7.97705 H 015 471
27153 TP27153 Tullygerravra G none 3rd order 54.37328 -7.97705 H 015 47

As with many things on TrigpointingUK, the data has been largely crowdsourced, and the provenance is weak! Many of these records predate the release of data by official bodies. For OSGB36, I have subsequently matched up the T:UK data to the official records and added a box to the trigpoint details page. I intend to do the same thing for the UK's Active and Passive stations at some point too.

However I'm unaware of any official OSI data from Tailte Éireann. If you have a link, please send it!

Many of the existing T:UK records in Ireland were "hacked in" by members, using the fact that the OSGB36 coordinate system is surprisingly wide. Since the re-write, the site now fully supports OSI grid references, has boundaries for the Irish countries/counties/coastline etc, which makes it easier to add new Irish trigs; but it also restricts adding trigpoints only to site admins, which makes it harder!

The current aim is to get the T:UK data aligned with the only maintained source of Irish trigpoints that I'm aware of, which is Graeme Patterson's spreadsheet. I have merged the contents of this spreadsheet into T:UK, and have removed many duplicates (though clearly not all, as Ted points out!). An admin page tells me that there are still 771 differences between the two sets of data However many of these are minor, and potentially justifiable (eg where our crowd sourced coordinates appear more accurate than Graeme's spreadsheet... provenance be damned!).

So, behind the scenes, the T:UK admins get hundreds of tiles like this, grouped by type and ordered by severity, that highlight the differences between T:UK and other data sources, and can choose whether to edit the T:UK data accordingly...

NB if anyone is looking at the above image and getting an uncontrollable urge to go and edit the T:UK height value, while taking care, in this particular case, not to update the stn_number or coordinates, then repeat x766... let me know and I'll make you an admin!

Hi

I recently submitted an FOI to Tailte Éireann for a full list of Irish trigs. It was refused, I appealed, it was refused again:

"Tailte Éireann considers that the disclosure of precise location information relating to triangulation stations, benchmark infrastructure and associated geodetic reference points could reasonably be expected to prejudice or impair the integrity and security of the State’s geodetic surveying infrastructure."

Most annoying. If anyone fancies trying again - strength in numbers might force a change in position? - you can email [email protected] . Note that you do not need to live in Ireland to submit a request, nor do you need to provide an address - just an email will suffice.

Thanks
Ross