How to use Mapio Cymru as a Welsh-language base map on your system

A couple of people have asked me how to use Mapio Cymru as a base map on their websites, apps, and other systems. This is a good way of providing visitors to your website with a map of Wales in the Welsh language.

In other words you can show our map tiles, which are the PNG images available through

Then you can do whatever your system allows such as panning, zooming, and perhaps putting pins, shapes, images and other things on the map.


Before we press ahead, everything that follows is aimed at somebody who is comfortable coding, maintaining a system, or using GIS software.

If you DON’T want to work directly with the base map it’s possible to embed Mapio Cymru on a website. This is probably the fastest and simplest method. It’s very similar to how you would embed video players etc (using an iframe).

Go to and click Rhannu/Share for details on how to do this. You can get an HTML embed code or alternatively a direct link to a specific view of the map.

Which systems?

The rest of this blog post will describe how to use Mapio Cymru as a base map, for people who want to be a bit more technical.

There are quite a few systems that offer to set a base map of your choice, such as things that run Leaflet.js, e.g. Overpass Turbo.

For example there are a few WordPress plugins that allow you to show maps on your website – such as Leaflet Maps Marker, WP Go Maps, and others.

If you have the skills you could create a website from scratch with Leaflet.js and use Mapio Cymru as a base map. Unfortunately the details on how to do this go beyond this little guide today, but there are guides on the web!

There is also desktop software that uses base maps of your choice such as QGIS.

For those interested Mapio Cymru’s CORS headers now allow direct use of tiles. Please note that some content management systems may show a security warning about cross-site scripting.

The all-important settings

Use the address below as the base map:{z}/{x}/{y}.png

Also if you have to give levels of zoom, put 3 as the minimum and 16 as the maximum.

Here is an attribution or credit you should give, to fulfil the open licensing conditions of OpenStreetMap data. Here’s the HTML version:

Defnyddiwch <a href=”” target=”_blank”></a>. Data ar y map &#x24BD Cyfranwyr <a href=”” target=”_blank”></a>

Alternatively here’s the plain text version:

Defnyddiwch Data ar y map © Cyfranwyr

Get in touch

If you have managed to get the map on your website or system, please leave a comment with the method you used – and a link to the specific page on your website if possible.


Please be respectful and reasonable with your use of the Mapio Cymru server. Get in touch if you want to discuss ‘heavy’ use, especially if you are an organisation, service, or project of significant size.

We’ll have to review how things go if demand grows.


Command-line tools for you to create an OpenStreetMap-derived base map in the Welsh language

All the custom code which we use for the Mapio Cymru Welsh-language map server is now available in a repository.

This will be of particular interest if you want to provision your own server which produces map tiles in the Welsh language (or perhaps a different language of your preference). All code is licensed under GPL, allowing you to run it for any purpose, modify it, and redistribute it.

Please note that a basic knowledge of how to use the Linux command line is assumed.

The main tool is a Lua script called cartonamecy2name.lua which is run when importing data. It determines the name to be stored in the database, for any given entity on the map. OSM data is the main source for Mapio Cymru, particularly the name:cy and name tags, and also Wikidata name information via OSM’s wikidata tag. In editing these sources we also refer to open data from the Welsh Language Commissioner.

Many more details are given in the README file in the repository, including step-by-step instructions for use.

If you just want to use a Welsh-language map which already exists, ignore the above and head to!


Put your organisation on the map : FREE workshop

Putting your organisation on the map for FREE!


Welsh Government is sponsoring a Welsh map to promote events in Wales.

As we move towards 2022, find out how to put your events on the map for free.

Join our mapping expert Ben Proctor of Herefordshire 3rd sector organisation Data Orchard & David Wyn of at 11am this Wednesday 1st December on Zoom

as they explain how the WG’s @MapioCymru could help you promote your events on an embeddable map for your website at no cost to you.

Guides Events

VIDEO: Gweithdy Mapio Cymru, Eisteddfod AmGen 2021

This post is a video recording of our event Gweithdy Mapio Cymru held at Eisteddfod AmGen 2021.

The video is entirely through the medium of Welsh.

In the video we discuss:

Diolch o galon i Eisteddfod AmGen a’r Lle Hanes am y croeso, ac wrth gwrs i bawb a gymerodd rhan yn y gweithdy!


Fun with Wales’ map data: a tutorial using Overpass queries and OpenStreetmap

Map: places in Wales that have ‘llan’ in their names

Would you like to get castles, rivers, post boxes, or cycleways in Wales from a map?

How about investigating place names in Welsh in your local area?

How about getting other features in Wales and further afield, as open data from a map?

This blog post will show you how to get open data from OpenStreetMap, with a particular emphasis on Welsh-language data.

It is intended as a fun introduction, not as a comprehensive reference guide. No previous experience is necessary.

We will be passing queries to the Overpass API, and it’s easy to get started. The queries can be run from your web browser in Overpass Turbo, which is one seriously cool app. Other than that your curiosity is the only prerequisite!

Introductory concepts

Feel free to skip this section if you want to head to the practical bit straightaway.

OpenStreetMap is a global map which has been built by thousands of people. It uses a wiki-like approach to mapping – anybody can edit and re-use the content. Because it’s all open data, you can use it however you want in your own learning, work, and leisure.

There is a huge amount of Welsh-language data in OpenStreetMap.

It’s independent of proprietary mapping providers, allowing you freedom to work with the data in your own projects.

The underlying code is also freedom-respecting software and open source. As the Mapio Cymru project we have built a showcase map which shows Welsh-language names for features including places, roads, rivers, and so on.

How to run an Overpass query

The quickest way to try Overpass queries is to visit the Overpass Turbo website.

The screen will be divided into an editor panel and a map/data viewer panel. Now do this:

  1. Write (or paste!) a query into the editor.
  2. Click the Run button.
  3. The results are shown in the data viewer.
  4. Within the data viewer you can select Map tab or the Data tab.

You’ll be following these same steps every time you run a query.

Towns query

Here is a simple query you can use. First drag the map and zoom until it shows an area you want to investigate, e.g. a part of Wales. Then follow the above steps using this query.


Bingo, you should now see towns plotted on the map area you’ve selected. Congratulations on accomplishing your first Overpass query!

The data

Select the Data tab in the data viewer to see the data. It will be in the default format, which is XML.

Here’s a portion of the XML data you’ll see for the results of the above query, for two towns:

<node id="8997358" lat="51.5912466" lon="-2.7517629">
  <tag k="name" v="Caldicot"/>
  <tag k="name:cy" v="Cil-y-coed"/>
  <tag k="place" v="town"/>
  <tag k="population" v="11200"/>
  <tag k="postal_code" v="NP26 4"/>
  <tag k="wikidata" v="Q722585"/>
  <tag k="wikipedia" v="en:Caldicot, Monmouthshire"/>

<node id="21413062" lat="51.8591257" lon="-4.3115907">
  <tag k="is_in" v="Wales"/>
  <tag k="name" v="Carmarthen"/>
  <tag k="name:br" v="Caerfyrddin"/>
  <tag k="name:cy" v="Caerfyrddin"/>
  <tag k="name:en" v="Carmarthen"/>
  <tag k="name:ja" v="カーマーゼン"/>
  <tag k="name:la" v="Moridunum"/>
  <tag k="name:ru" v="Кармартен"/>
  <tag k="place" v="town"/>
  <tag k="population" v="14185"/>
  <tag k="population:date" v="2011"/>
  <tag k="source" v="NPE"/>
  <tag k="source:population" v="Census"/>
  <tag k="wikidata" v="Q835835"/>

As you can see, the name:cy tag has the town’s name in Welsh. There are equivalent tags for other languages. There’s also a tag called name without a language code, here’s the definition of the name key.

In general name:cy will provide the name in Welsh for anything on the map – if it’s been submitted.

The other data in the examples above should be fairly self-explanatory, and include latitude and longitude, Wikidata item identifier, and other things.

Note that OpenStreetMap is always a work in progress. You’ll see pretty good data for many queries although some others will display gaps. (You can edit/add place names on the map, and other features and their tags.)

Change your Overpass Turbo map to Mapio Cymru

Within Overpass Turbo your underlying map will probably be the main OpenStreetMap. This is OK but it won’t always display all names in Welsh.

You can change it to the Mapio Cymru map server, like this:

  1. Select Settings menu
  2. Select Map
  3. In the Tile-Server box put: //{z}/{x}/{y}.png

Please note that when you click on map pins any links will still go to the main OpenStreetMap.

Farms, cities, and other places

You can take the query above and modify it:


Spot the difference between this query and the one above. Alternatively use one of the possible key values for place. For example you can use “village”, “city”, “island” and so on.

Your bounding box

In general:

  • If your query refers to a bbox (bounding box) the query will run on the visible map, the portion of the map you’ve selected.
  • You can also reduce the width of the map: drag its edge to reduce its size, and increase the size of the editor.
  • If your query has a lot of results, there may be too much data to plot on the Overpass Turbo map in your browser. Try zooming in to reduce the size of the bounding box.

Towns in Wales only

No matter how much you move the bounding box it’s not possible to get all of Wales, and Wales only. Our query needs to change.

This time, click the Wizard button and type ‘towns in Wales’ then click Build Query. When I ran it it suggested ‘town in Wales’ then gave the following query, and yours will be similar or the same.

This has been generated by the overpass-turbo wizard.
The original search was:
“town in wales”
// fetch area “wales” to search in
// gather results
  // query part for: “town”
// print results
out body;
out skel qt;

Where possible the Wizard will take the English you type and give a query in Overpass query language. As far as I know the Wizard is only available in English at the moment.

searchArea above is a variable containing our geocode area for Wales. It is set for the life of the query. We don’t have to call it searchArea, we can call it almost anything – as long as there’s no clash with other reserved terms.

The above query contains comments which have no effect on the query. There are two styles:

/* comment within slash star delimiters */

// comment between double slash and end of line

Llan place names

As well as Llanelwy this will return Rhosllannerchrugog in the results – and so on. It’s a case-insensitive search.

out center;

This is a narrower search for Llan with a capital L.

out center;

Here’s a search that includes the tags name a name:cy for a comprehensive map which includes places which currently lack a name:cy tag and names like Llanandras (Presteigne) and Llanllieni (Leominster) (diolch/thanks for your replies via Twitter!).


This will give all places in Wales with Llan in the name. It gives data only – in Overpass Turbo the map tab will be blank. You can use the CSV results data in a project, e.g. in a spreadsheet.

[out:csv("name:cy", "name", ::lat, ::lon, "place", ::id; true; ",")][timeout:50];

You could modify one of the above for ‘Aber’, ‘Caer’, ‘Tre’ and so on.

Castles in any area

Now try this query.

// gather results
  // query part for: “castle”
// print results
out body;
out skel qt;

This is OK but how about all the castles in Wales only? Use this:

// gather results
  // query part for: “castle”
// print results
out body;
out skel qt;

Here are some others to try. In each case you should edit the three statements above to cover all nodes, ways and relations in the search. Let’s look up the definitions of those in a jiffy…




"amenity"="bicycle parking"


"amenity"="bus station"

The last one will identify, among others, the National Express coach station in Cardiff – currently the only bus station in the city.

Elements of OpenStreetMap

There are millions of possible Overpass queries.

You can play around with basic queries without having a comprehensive understanding of OpenStreetMap. The wizard may help.

Sooner or later though you might want more context to help you write that special query for your own interest. This portion from the documentation on elements has some vital definitions will help:

Elements are the basic components of OpenStreetMap’s conceptual data model of the physical world. They consist of

  • nodes (defining points in space),
  • ways (defining linear features and area boundaries), and
  • relations (which are sometimes used to explain how other elements work together).

All of the above can have one or more associated tags (which describe the meaning of a particular element).

If you want to see some examples of nodes, use this query.

In Overpass Turbo this will only work for small bounding boxes, because the amounts of data are relatively large.

Show the Wales Coastal Path

This is a simple query that only shows one relation – the northern part of the Wales Coastal Path.


This shows the entire Wales Coastal Path. (Because this is stored as a relation of relations, the query uses a ‘recurse down relations’ operator >> to display the relations, ways, and nodes within the overall relation. Here’s more info on the recurse down relations operator.)


Hiking routes

Taken from the Overpass API examples. You probably need to zoom into a bounding box.


{ color:green; fill-color:green; }

relation[network=lwn] way
{ color:blue; fill-color:cyan; }

relation[network=iwn] way
{ color:red; fill-color:red; }

relation[network=nwn] way
{ color:green; fill-color:green; }

relation[network=rwn] way
{ color:yellow; fill-color:yellow; }


Rectangular buildings in Wales that are taller than they are wide

This one’s adapted from the examples.

// Find rectangular buildings that are taller then they are wide
  // Compare the height to the average length of a side
    count_members() < 6 && is_closed() &&
    number(t["height"]) > length() / 4);
  // Assume a floor is 3 m tall
    count_members() < 6 && is_closed() &&
    number(t["building:levels"]) * 3 > length() / 4);

// Print results
out body;
out skel qt;

What’s next? Edit the map

If you notice any deficiencies in the data then you can edit the map. Welcome to the open data mapping community!

Overpass can be used deliberately to look for opportunities to improve the map.

Overpass Turbo in Welsh?

Overpass Turbo’s interface is available in a few languages but it doesn’t offer Welsh as an interface language yet. If you’d like to contribute to the translation head to its Transifex project.

Write your own queries

Start with the Overpass Turbo examples and Overpass API examples provided by the OSM community.

You can even delve into the user manual for Overpass.

Using Python instead of Overpass Turbo

If you can use Python you can run Overpass queries in your code using this simple wrapper instead of the Overpass Turbo web interface. Write an app and wow us!

Alternatively check out these other methods of querying Overpass via code.

In any case Overpass Turbo is handy for perfecting your queries.