Mapping Ireland's 61,000 administrative boundaries

The really, REALLY long way from Abartagh to Youngstown

Created by Rory McCann & Dave Corley @DaCor_ie


Lowest level of Ireland's administrative hierarchy

boundary=administrative admin_level=10

Very small - Traditionally the amount of land one extended family could live off.

Very old - Date back about 1,000 years


Why not?

This is an OpenStreetMap conference, do we need to explain why you wouldn't map something?



Anyone geocoded Irish addresses? It's a mess.

Houses in rural Ireland don't have house numbers, postcodes, or street names. Instead using (sometimes) "House Name, Townland, Nearby Town, County"

Townlands are important and helpful for geocoding many addresses.

Newly introduced postcode system (Eircode) might change that


Other administrative boundaries

Townlands are atomic unit of other administrative boundaries

Larger administrative boundaries are made up of townlands.

Electoral Divisions (NUTS LAU), Constituencies

Can now add those to OSM

Can now use Irish official government data which is keyed on ED


History and Heritage

Part of Ireland's cultural heritage and should be preserved and spread.

19th/early 20th century census records are sorted by townlands.

Helps people searching for Irish ancestry/genealogy

Names record a history

e.g. Passifyoucan, Co. Dublin. Used to be the site of a lot of highway robberies

Open Data

Can't we import some open data from the government?

No. Not available, incompatible licence or simplified

So how do we do it?

Townlands not signed on the ground.

Borders aren't marked clearly

So how do we do it?


Most maps now a days don't show townland borders

Or other borders. Only counties (admin_level=6)

Tax authorities to the rescue!

19th Century British tax authorities

Ordnance Survey - First edition

From 1829-42 the Ordnance Survey mapped Ireland for tax purposes

Made some beautiful Six Inch to a Mile (1:10,5600) maps ("First Edition")

Clearly show townland borders

Copyright has expired!

Ordnance Survey - First edition

Aside: Historical tidbits

Population of Ireland has halved since then. (Famine in 1845-52 & emigration ☹)

Ireland was probably one of the best mapped countries on the planet at the time

Nice easy to read maps

These are ~2,000 large sheets from 150 years ago.

Problems: Only a few libraries and universities physically have them

Ordnance Survey Ireland have a copy

Scanned in!

Cropped and rectified!

On the web


Claim copyright ☹

Need another source

1829-42 - First Edition of 1:10,560

1910s - Third Edition of 1:10,560

1922 - Ireland gets independence from the UK

1939 - WW2 starts

1940 - UK war office, thinking they might need maps of Ireland, fall back to the 3rd Ed.

Re-scale 3rd Ed 4:1 to produce GSGS 3906 maps

Glucksman Map Library, Trinity College, Dublin

Glucksman Map Library, in Trinity College, Dublin had a scan

They will give us copies for OSM, if we'll scan and rectify for them


Let's get rectifying

Upload the images to Map Warper (

About ~675 images

Community starts cropping, rectifying and mapping.

Remember the 6 inch map?

Quality 😕

This is what we have to work with. Can you spot the townland borders?

Quality 😕

This is what we have to work with. Can you spot the townland borders?

Let's get mapping

OK, it's hard, but let's do it

Some things to make it easier

Some tools to help

JOSM preset and map paint style

Slippy map



All mapping was done in JOSM

Much easier to include custom imagery layer(s)

Custom map paint style to display mapped Townlands (etc)

Custom preset

Validator for multipolygon relations

Lots and lots of relations! - Slippy map

We set up a replicating slippy map tile server which shows the mapped townlands (etc).

Allows people to see mapping progress as it's done.

Missing townland? Maybe incorrect relation

Rory set up

Django web app that imports OSM data and displays it formatted

Includes progress reports and rates of mapping, to spur people on.

YouTube videos

Dave made video tutorial on mapping townlands

2½hrs of video

Covers all aspects of georectifying a sheet, using JOSM, mapping the townland, and other areas

Led to some new mappers coming out the woodwork and contributing

Townlands are building blocks

Townlands are administrative building blocks

Map all the boundaries

While adding townlands, we can now start adding higher level administrative boundaries

Civil Parishes

Based on Church of Ireland (Anglican) parishes

Church of Ireland was disestablished in 1871

Not used much any more for state purposes

Very useful for genealogy, since old census, birth certs include CP as a field



Each county is split into a few baronies

Not used much anymore, nor used a lot historically


Electoral Divisions


Constituencies (which are often changed) are legally defined by EDs (mostly)

Official statistics (Census) use EDs

EU level statistics area (NUTS / LAU)

Some stats

There are 60,513 townlands

First townland added in 27th June 2010

Last added 25th August 2016

Who's mapping?

Lots of people, but core of hardcore mappers

Who's mapping?

Who's mapping?

Local mapping.

People started mapped their local area or area they had a connection to.

And then spread out

People care about areas, and wanted to improve that area

Who's mapping?

Not very diverse in some ways - mostly male

Diverse in age

Rate of mapping

Keep on mapping!

Mapped townlands

One problem

Since townlands are small, there are now tens of thousands of tiny relations all over Ireland


Seemed impossible in 2010

But we did it!

Tools & resources are important.


Most mapping done by small number of people

But they're not necessarily the people you think, or that you know about

Setting a complex task is all well good, but for success you need to come together and build on what you are best at

Some are techies, some are teachers, some are motivators, all are important

You have to get out there and tell people, in order to find the dedicated mappers


Glucksman Map Library, Trinity College Dublin - provided the GSGS 3906 maps

Bodleian Libraries, University of Oxford who provided some missing GSGS 3906 maps

Map Warper - vital web based map rectifier (Sorry for filling your disk!)

Blueprint Reprographics - Dublin printing company that helped us scan in some of the large map sheets we have

Thanks to Govs

Thanks to the governments of Ireland and Northern Ireland

Both have (now) released townland data, albeit generalised, in an open licence

Just before we finished

Wasn't that nice of them?

The Future - What next?

Can utilise government's open data (EDs)

Map more accurately - Dramatically improved county borders

Donate the rectified images back to the libraries

Currently matching & importing official Irish place name data (logainm) to get better name:ga coverage


(Oh dear god don't have to stare at those ancient maps anymore)