Update on thatched building mapping

Posted by b-unicycling on 3 August 2022 in English. Last updated on 5 August 2022.

Disclaimer: yes, I know, it’s absolutely micro mapping, but see “Side effects”.

It’s now been about 4 weeks since I started mapping thatched buildings in Ireland more systematically than just ad hoc adding roof:material=thatch whenever I saw one. I had focussed on Co. Kilkenny, because of a 1994 survey carried out by thatcher and archaeologist Jimmy Lenehan in that county, so all I had to do was revisit the sites and check whether the roof:material was still the same. I ended up visiting about 58 of of the 106 sites in his survey. (I tried to remember to add survey_date to those, so I could run an overpass query.)

He also told me about some newly thatched buildings, where I could add the tag, too.

I also had a long talk with him in his own thatched house which was a very interesting experience, because it was a very warm day (for Ireland), and the thatch really did insulate the house really well. He is not very good with technology, but I think he understood the potential of mapping the thatched buildings on an OpenData platform. I’ve added ref:IE:lenehan to the buildings from his survey and documented the tag in the wiki.

I also had a chat with our Heritage Officer who thought it was a good idea to undertake a new survey, but doesn’t seem to grasp the advantages of crowd sourcing and OpenData quite as much as I would hope. She is under the impression that I’m only doing a photographic survey, because I told her that I was uploading the photographs to WikiCommons (about 82 uploads for Co. Kilkenny so far). She asked if I would provide these images to their county archive as well, because “not everybody knows how to use that OpenData thing”. Well, everybody knows how to use Google, that should bring them to WikiCommons straight away. So I politely explained that and declined providing duplicate content. Needless to say, there is also no public funding for a survey this year, so I’ll just soldier on in my own time and out of my own pocket.

I had chats with some residents of thatched cottages, especially in South Kilkenny where they are concentrated. I still believe it is because of the rivers as the natural habitat of the material rather than the thatchers. In my third video, available from Aug 6th of my thatched buildings series and the uMap, I think it becomes quite obvious. I’m not saying that there is no correlation, obviously there will be or were more people thatching in an area where the material was/ is grown, but the material was there first.

distribution of thatchers in the past and thatched buildings distribution of rivers
Thatchers c.1880-1930 and thatched buildings 2022 main rivers and thatched buildings

Thatching history of buildings

I was able to ask those residents/ owners of thatched buildings when their buildings was last thatched and by whom. I added that information as thatch_date (not documented yet, but similar to start_date) or, where applicable, thatch:end_date (also not documented). I also got some of that information from the two thatchers I’ve spoken to so far, and I have to catch up on adding that information still.

thatch dates thatch dates on overpass

I’ve also added thatcher_name with the information given by the owners or what I found in Jimmy’s survey or from the other thatcher (Matty Kelly) I talked to. This one is documented in the wiki. Sometimes, I got a whole biography of a roof, so to speak.

distribution of thatchers overpass for thatcher_name

Protected structures

I also added ref:IE:niah (documented) for those buildings on the National Index of Architectural Heritage which was quite sobering, because since the government’s last survey, quite a few buildings have lost their thatched roof and therefore their qualification to be on that list (I presume). A new survey by the ministry is planned for the next two years, I believe. (See “side effects”).

Side effects

Yes, it is very much micro mapping or even smaller than micro, but on the one hand, I’m trying to make a point to show the authorities what OpenData can do, and on the other hand, a lot of collateral mapping got done along the way:

Working with the authorities

While trying to locate the thatched buildings and adding their ref:IE:niah, I sometimes found that their location on the government map was wrong, so I contacted the department with my alternative locations, and they were implemented over night. Thank you, Damian!

I also created a concordance of the numbering in Jimmy’s survey with another survey conducted by the Office of Public Works in the same year and provided it to our local Heritage Council with annotations of which buildings were no longer thatched.

Rural mapillary

As I was visiting the sites, mostly on public transport, on my bike or on foot, but also one trip in a car, I took mapillary footage of very rural areas where usually nobody else goes: South Kilkenny, Callan area.

New roads

Especially on two round trips on my bike near Callan, I took very minor roads and discovered one previously mapped as an incomplete track, which turned out to be a connecting road.

I furthermore discovered a reference number for a minor road which had been classified as a service road before. I felt quite like an explorer. :D


Since I was depending on public transport so much, I sometimes had over an hour left before the bus home went, so I used that time SCing Callan (mostly). I always try to kill at least two birds with one stone, so when I was stuck for transport home after a gig with my band, I took an AirBnB and surveyed that village in the evening and continued on the next day to meet a thatcher. house numbers in Durrow Previously no house numbers and no building site mapped and wrong or missing street names

(I’m probably forgetting things here…)

Public transport routes

Since I had to take unmapped bus routes, I tracked them on OSMAnd and added them to OSM. They’re incomplete, because I didn’t need to go the whole way, but at least it’s definitely ground truth.

Bus route 828


I tried to be very thorough when I uploaded the photographs and added as much structured Wikidata as possible (like the townland for every photograph, viewpoint location and object location) to make the images as useful and accessible as possible. I learned a bit along the way, but might have made some mistakes, because I hadn’t done this before.

And when I came across a castle or a lime kiln along the way, I took pictures of those as well, obviously, and uploaded them.

Work experience

I also got to help Matty out one day preparing the scallops for thatching, but that’s got nothing to do with mapping…There might be a video on my channel in the future.

Radio interview

I was also interviewed for the local radio, but the interviewer “got confused” about OSM, so his questions didn’t focus too much on that, unfortunately. I tried, I really did. It’ll be broadcast August 7th, I believe.


I’ll continue with this for another while. I’m also hoping to talk to our Minister for Heritage, Something, Something and Housing (I can never remember, he’s Malcolm to me) about the need for more support of owners of thatched buildings and the need to preserve areas where water reed is grown. I had learned from Matty Kelly that many farmers in South Wexford (an area quite known for its thatched buildings) are draining fields, so that water reed cannot grow there any longer. Have I mentioned that it is imported from Turkey and the Ukraine? Not very sustainable. (I was going to meet the minister in a different matter anyway, but people have suggested that I should bring it up with him.)

I might write a paper about this at some point, focussing less on the mapping and more on the heritage (grown and built) angle, but of course promoting OSM. Try to stop me!

Sin é bhfuil. Thanks for reading until the end.

Location: Clasharoe, Portnascully, The Municipal District of Piltown, County Kilkenny, Leinster, Ireland


Comment from kakiremora on 15 August 2022 at 10:51

Quite beautiful micromapping!

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